Core Heavyweight Zip-T - 2018

Core Heavyweight Zip-T - 2018

  • Big Game : Open Country
$129.00 $64.50
(26 Reviews)

With lofted fleece insulation and a high zippered neck for fine-tuning your microclimate, the CORE Heavyweight Zip-T keeps you toasty on frigid, low-activity hunts. Permanent Polygiene® Odor Control Technology neutralizes odor by stopping the growth of odor-causing bacteria and fungi. The CORE Heavyweight Series is the next-to-skin foundation for static hunts in cold weather, with a body-mapped grid fleece backer that retains warmth while actively moving moisture away from the skin.

Product is Performance Fit, designed for minimal layering.

To be notified when an out-of-stock product is available, please select your size and click the "EMAIL ME" button.

GORE™ OPTIFADE™ Concealment Open Country is scientifically optimized for engagement ranges of 50 yards and beyond at ground level in rocky terrain above the timber line.

Sizing Guide

Jacket & Tops Sizing

Size Chest Sleeve
Small 36 - 38" 33"
Medium 39 - 41" 34"
Medium Tall 39 - 41" 36"
Large 42 - 45" 35"
Large Tall 42 - 45" 37"
X-Large 46 - 49" 36"
X-Large Tall 46 - 49" 38"
2XL 50 - 53" 37"
2XL Tall 50 - 53" 39"
3XL 54 - 57" 38"

Pant Sizing (Inches)

Size Waist Reg Tall
30 30" 31"
31 31" 31"
32 32" 31" 33"
33 33" 32" 34"
34 34" 32" 34"
35 35" 32" 34"
36 36" 33" 34.5"
37 37" 33" 34.5"
38 38" 33" 34.5"
40 40" 33"
42 42" 33"
44 44" 33"

Pant Sizing

Size Waist Reg Tall
Small 28 - 30" 31"
Medium 31 - 33" 31" 33"
Large 34 - 37" 32" 34"
X-Large 38 - 41" 32" 34"
2XL 42 - 45" 32" 34"
3XL 46 - 49" 32" 34"

Equinox & Dakota Pant Sizing

Size Waist Reg Tall
30 31" 31"
32 33" 31" 33"
34 35" 32" 34"
36 37" 32" 34"
38 39" 32" 34"
40 41" 32"
42 43" 32"
44 45" 32"

Glove Sizing

Size Palm Circ Length
Medium 8 - 8.5" 7.5 - 8"
Large 9 - 9.5" 8.5 - 9"
X-Large 9.5 - 10" 9 - 9.5"
2XL 10 - 10.5" 9.5 - 10"

Gaiter Sizing

Size Calf Circ Boot Size
M/L 17.5" US 6-10"
L/XL 18.5" US 10-14"

How to Take
Your Measurements


    Bend your elbow and put your hand on your hip. Measure from the center of the back of your neck, along the shoulder and down the elbow to the wrist bone.


    Take measurement under armpits, around fullest part of chest and shoulder blades.


    Measure around where you normally wear your pants, keeping the tape measure a bit loose or putting one finger between your body and the tape measure.

  • 4. INSEAM

    In a standing position,measure from your crotch to where you want your pants to end, breaking at the top of the shoe in the front and just above the heel in the back.

  • 5. GLOVES

    With hand partially closed, measure over the knuckles, around the hand, excluding the thumb.

Fit Guide

SITKA Gear engineers gear with a specific Fit and intended end use in mind. These functional designs provide the user with authentic garments for the right situation.

Fit Descriptions

We can communicate our Fit descriptions in 3 different ways. Keep in mind that each garment will allow for layering in accordance to the garments place in a system and described Fit

  • P/F
  • S/F
  • E/F

    Designed for minimal layering. Whether an early season piece or already insulated this garment fits to prevent inefficiencies in heat retention caused by dead space.


    Designed to accommodate layering for more versatility from early to late season climates.


    Designed for maximum layering in the worst conditions. Cut roomier to accommodate additional layering underneath.

Back to Shopping
Performance Fit

Fit Guide

SITKA Gear engineers gear with a specific Fit and intended end use in mind. These functional designs provide the user with authentic garments for the right situation. We can communicate our Fit descriptions in 3 different ways. Keep in mind that each garment will allow for layering in accordance to the garments place in a system and described Fit.


    Designed for minimal layering. Whether an early season piece or already insulated this garment fits to prevent inefficiencies in heat retention caused by dead space.


    Designed to accommodate layering for more versatility from early to late season climates.


    Designed for maximum layering in the worst conditions. Cut roomier to accommodate additional layering underneath.

Back to Shopping


  • Product Care: Routine Care and maintenance ensures the optimum performance of your SITKA Gear. Be sure to follow the manufacturer’s care instructions – typically found on the inside tag: - Machine Wash Cold Delicate + Tumble Dry Cool - Do Not Bleach + Do Not Dry Clean



Product Comments

26 Reviews
Write a Comment
Ross Evans
Reviewed On 12/12/2018

Core Heavyweight is a quality garment and one I would recommend to anyone, that being said, I think the Merino Heavyweight is better! By no fault of Sitka the Core gets that familiar "chill" that all poly garments seem to get when you sit in a tree stand in very cold conditions. As far as Sitka Core vs UA or other "high end" base layers I would prefer Sitka's to the any of the many others I have worn in my hunting life. Sitting in a tree stand in MN and WI like I do it brings "warm weather" gear to the true test. This is a fantastic piece. I will continue to wear it often but when the really cold days come, I will be wearing Merino. If you don't like Merino fabrics, this Core is as warm as it gets!

Sean R
Reviewed On 11/26/2018

Love this garment. I use it as a "mid layer" over a merino wool baselayer for the hike in. While I'm a little cold to start, I prefer to have less layers on and warm up as I hike rather than shed layers because I'm sweating/too hot. I use an insulated vest on top of this to break the wind and then store the vest away as I continue to hike if necessary.

Warmer days I'll just use this as a base layer, as we're still hiking at approx. 10,000 ft.

Note, it is NOT windproof, and isn't intended to be. It is great for some warmth and outer layer on a warmer day during 3rd rifle season in CO - as others have indicated, think of it like a form fitting sweatshirt that mitigates body odor and provides extra warmth.

Lee W.
Reviewed On 11/09/2018

This hunting article is "The Best of Everything SITKA." True statement. This is a mid layer "sweat shirt" with one chest pocket with zipper. Perfect place to put your cell phone. Pocket could be slightly larger, like another inch. Often in the mornings, I start with an underlayer and this sweat shirt and the "Jet Stream Jacket." As the morning warms up, I put this sweat shirt into the backpack and keep hunting. There are several underlayers to choice from, but my favorite is the long sleeve t shirt "CORE LIGHTWEIGHT CREW LS" When the temperatures climb this will be your t shirt and it's nice to have several (clean) of these to change into during a long 7 day elk hunt. Now, when I'm back at camp this is my favorite most comfortable sweat shirt... In fact, this is my favorite shirt to change into after a long day at work... hit the couch and watch some elk hunting videos.

Bairam, UK
Reviewed On 09/20/2018

Permanent Polygiene® Odor Control Technology - whatever it is, it just does not work. I tried to wear this during mountain hunt: uncomfortable synthetic feel and also smells horribly the next day.

Ronnie T.
Reviewed On 01/05/2018

Now that the 2017 season is over and I feel I’ve tested this particular item in a multitude of weather conditions, I felt very compelled to write a review of this product. This top will go beyond your expectations. Not once was my torso ever cold and if you pair it with the heavyweight bottoms, you’re all set for a base layer. And just for reference, I hunt in NY and CT where the season started in the 70’s and ended this past week well below 0 with the windchill. Even when it was 20 degrees out, I would just wear this top next-to-skin and a heavy shell jacket (regrettably not Sitka, but that will be changing soon). I also like how the backside fo the top is longer, being a bigger guy this was a really nice touch seeing as not all tops cover my entire back. This is well worth the investment and I can’t wait to build up my collection of Sitka gear in the future.

Reviewed On 11/28/2017

This was the first Sitka Product I purchased and it works great! Any temperature above freezing with little wind I can get away with wearing just this instead of a jacket.

Reviewed On 11/08/2017

One of the best Sitka products I own. This hoodie functions flawlessly. The hood is perfect for concealment and warmth. The fit is great and is long enough in XL for me. Iam 6'3 220 lbs and at times sitka can run a little short for me. However this garment fits perfectly. Couldn't recommend it more.

Reviewed On 09/26/2017

Absolutely love this piece! Great for early season with the Core LS underneath, and then able to layer up during late season. Only small down fall is I wish it had some sort of pockets for your hands at the bottom. However very small issue as I usually have a vest over it or it is under my waders. Great piece as always!

Ray Clark
Reviewed On 07/13/2017

The core heavy weight base layer is a must have in extremely cold weather! If you are stand hunting or blind hunting this layer combined with the right outer layer will let you do all day sets! And be very comfortable! If you are doing spot and stalks in very cold weather you will burn up! You only want to wear this if you are sitting still! Love it

Reviewed On 03/20/2017

Hi I was thinking about getting sitka because I hear it's very comfortable, light, not bulky, and love some of they're camo but couple things that really pushes my buttons is the money sucking and the 1000 different layers they say you this is the "heavy weight" "and will keep you toasty" but then they say you'll need 2-3 layers underneath this and 1 or 2 on top of this plus the incinerator on top of those in like 30 degree temperatures....that's like $2500 1st off and 2nd if the incinerator or whatever the main jacket and pants are called are so warm then you shouldn't need all this extra clothes other then a simple cheap 1st layer silk and a layer like this jacket and that's it. I know from what I was reading that the incinerator is comfortable and all that but if you need 7 layers underneath it then it must not be so warm of a jacket. I will have to try it on but I have been burned by scent loc/scent blocker which they're products suck...don't ever buy scent loc/block. And also the main reason I was excited about sitka incinerator is because my state has late archery on December 26th-January 30th and usually freezing so I have to put on all these layers and im too bulky to shoot my bow (like randy from the christmas story-can't put my arms down) and my rifle clothes are too loud for archery, so when I hear a jacket is on the market where it's as bulky as my clothes usually would during late October but it will keep you warm in January I was pumped up but then I see videos and comments that you need to put on 1st, 2nd, 3rd, 4th, 5th, 6th, 7th 8th layer then the incinerator I was bummed out to say the least then to know all the layers underneath and that equal around $3000 it really bummed me out....hunting clothes should not cost that much.

Eric Wittman
Reviewed On 12/11/2016

I've been wearing this item on the Delmarva Peninsula since we got into the low 70s for highs and haven't stopped wearing it. I'll walk 1-2 miles with my stand and pack (42#s Total) every time i go out. I gotta have plenty of food and drinks or forget it. I typically sweat like a monster. With this layer, I've been able to get to my setups and either stayed with it alone or stacked a shell. It's a pleasure not having the feeling someone threw a gallon of sweat on me. I can't stand when I'm drenched even before I climb the tree. This piece rocks. I've been using it with a Jetsream Lite Vest in 50-60 degree days and roll in a Traverse Zip T when it's 40-50 degrees. It's been this alone when i have the Downpour Jacket for rain. Now that we're in the 30s, the Jetsream has been replaced by the Celsius Jacket. Whatever else you're using, you need to get this as a base layer and stack & shed accordingly.

Mark M
Reviewed On 12/05/2016

If you hunt cold weather,this is a must have item.Whether your flat on your back in a ground blind, pit, or whatever your hunting situation. There is a big difference in this next to skin layer. and anything else on the market. Warm ,and very comfortable to wear. Weight to warmth ratio is amazing.

Reviewed On 11/26/2016

I'm not one to write reviews but after all the research I did and reviews read by others, I felt I needed to share my experience with Sitka. Conditions were 22 degrees, 15-20 mph wind and snow in the mountains of NY. I spent an entire week in these conditions and have never been so warm! I really liked being able to wear the hood when I walked into the woods keeping myself cool. I simply followed the layering system, and wow! I had Core lightweight shirt, heavyweight zip-T, fanatic hoody and fanatic jacket. This set up was perfect! Thank you Sitka!

Reviewed On 11/24/2016

Perfect base layer, I used it last weekend during a duck hunt in south east Texas. The temperatures were down in the 40's. used this along with a long sleeve shirt and was warm the whole hunt. Would not suggest wearing it by itself on a windy day. But for just sitting in a blind or on a calm day you can't go wrong.

John marleau
Reviewed On 10/02/2016

Very comfortable and somewhat warm. Paired this with a Sitka fanatic hoodie and stratus vest in +4 (Celsius) with rain in October up here in Canada. For the most part I stayed warm, am impressed.

Corbin M.
Reviewed On 08/05/2016

Hunting in the Mississippi delta, it rarely gets very cold except during late season. The core heavyweight zip-t is the perfect lightweight pullover, a surprising amount of warmth for being so light weight and the moisture whicking ability is incredible. I used to arrive to the blind and be drenched in sweat using other products, but with this pullover I stay warm and dry. It is a piece that you can roll up and store just about anywhere so it makes it very versatile.

David I
Reviewed On 07/12/2016

One of my favorite pieces I have. I'll throw this on over my crew ss in the early season when it cools off at night and when its cold in the later season, I'll walk in with this to keep sweating to a minimum (great a wicking it away) then throw on my other layers once I climb up into the stand. Very warm, lightweight, and packable. Extremely recommend

Coty S.
Reviewed On 03/02/2016

This is a great piece. I wore it scouting the other day. I put on about 6 miles in some pretty hilly country. It was fairly cold, but there were times I was sweating pretty good. This piece did an amazing job wicking the sweat away and then the piece dried extraordinarily quick, allowing me to stay warm while I was standing still. This will be a piece I can see wearing all season long.

John R
Reviewed On 02/18/2016

The new core items seem like an improvement over the old core and Traverse combination. I really like the weight of this fabric as a base layer in colder weather. I now prefer this item over my old UA setup. The fabric is quiet and wicks well. Just a nice thick shirt that can be worn by itself in chilly weather or combined with other items in colder weather.

chris s
Reviewed On 01/26/2016

Love this jacket. I have worn it in warm weather (~70 degrees F) to colder weather (just below freezing) and it has done great. Doesn't make me sweat on hot days during set up and keeps me warm on cold days. I haven't really had the need to layer over it but it fits pretty snug underneath my waders so it would be easy to wear a jacket over it if i wanted. I also like the pocket in front to keep my phone accessible but protected

Ben B
Reviewed On 01/20/2016

This thing is sweet. Unlike traditional compression base layers, this piece is comfortable and irritation free on the longest of days in the blind. The odor control technology makes the piece ideal for those hunts away from home (when the layer must be worn on consecutive days without washing),and more importantly, the deep zipper and fleece material allow the garment to be worn between duck camp and the blind without overheating.

Ron Duncombe
Reviewed On 01/11/2016

I have used this multiple times in a variety of conditions. Does a great job of keeping you warm and dry. And is extremely versatile in layering.

Dave Bush
Reviewed On 01/08/2016

This is a great piece of gear. It keeps me warm when coyote and elk hunting in the snow. It has kept me warm down to -10 degrees, with other layers. Sweat is wicked away to keep one warm.

JR Brown
Reviewed On 12/28/2015

GREAT Product. I wore it this past weekend on a hunt with it constantly raining and wind blowing really hard. it kept me really warm. I couldn't ask for more. ready to order some more products. I would recommend it to anyone

Remington Clark
Reviewed On 12/11/2015

I purchased this jacket this year with the hopes of warm mid layer that was versatile. I put this article to use in extremely varying weather conditions and in different layering set ups. It worked extremely well. Not only was it warm, but it was easy to layer and I didn't have to deal with a hood.

Tim Multerer
Reviewed On 12/01/2015

Where this only under your fanatic jacket or incinerator jacket and you are set for down to 10F and perhaps beyond. This shirt is like wearing a heating pad!

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Adam Foss - 04.26.2019

A Tale of Two Roars

Rustic wooden gates groaned open as our Toyota HiLux rumbled through. We navigated the rutted, winding dirt road; every pothole and washboard negotiated revealing another layer of the towering Andes Mountains. A gin-clear river meandered through the valley floor. Willows on the cusp of fall color shimmered in the cool afternoon breeze. This was the start of the annual breeding season for red deer in northern Patagonia—also known as the roar.