Big Game: Open Terrain

Kelvin Active Jacket 


A necessity for any true backcountry outing, the Kelvin Active Jacket features 80 gram Polartec® Alpha insulation for maximum versatility - an ideal outer layer in mild conditions and perfect insulation under a shell when the mercury plummets. Soft, quiet and breathable, this workhorse knows no off season.

  • Polygiene
  • Drirelease
Open Terrain
Ground Ambush, Spot & Stalk
Mild, Cool
Optifade Open Country
13.7 oz // Large
Other scenarios for the Kelvin Active Jacket
  • Size:

Cool Conditions

Open Terrain Spot & Stalk

A workhorse system designed to be lightweight and athletic to meet the demands of technical terrain while standing up to sudden drops in temperature and torrential rain, sleet and snow.

  • ALL: Mens
  • Pursuit: Big Game
  • Environment: Open Terrain
  • Activity Level: Highly Active, Active, Moderate
  • Temperature: Cool
  • Concealment: Optifade Open Country

Features & Benefits

Highly Breathable and Thermally Regulating

Polartec Alpha Active is a non-migrating lofted fleece insulation that offers superior breathability and moisture management. This versatile insulation allows us to construct a garment with a more open liner fabric, greatly improving breathability. By keeping moisture vapor moving freely through the fabric, it increases overall air exchange and speeds up dry times. This advancement increases thermal adaptability in changing conditions and different phases of physical activity.

Durable Water Repellent Finish

The DWR finish resists light precipitation and prevents the face fabric from wetting out.

Brushed Fleece Hand Zip Pockets and Interior Zip Chest Pocket

The zippered chest pocket secures your necessities and doubles as a stuff sack. Hand warmer pockets are lined with brushed fleece for added warmth.

Neck and Chin w/ Brushed Tricot Lining

The neck and chin are lined with a brushed tricot to prevent chafing and add warmth and comfort.


80 g/m2 Polartec® Alpha Insulation


Shell // 20 denier Nylon Ripstop
Liner // Breathable Polyester Mesh

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


Visit Care Guide
Product Comments
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Carl Abrams | 10. 26. 18
Love this jacket! I used the Kelvin Lite for years because most of my hunting doesn't involve bitter cold. While I had no complaints with the K Lite, the Kelvin Active improved on it. The fabric is nearly silent, it breathes well and the fit is great (the Tall version is the cat's meow for my frame). When I expect cool weather the Kelvin Active is either on my back or in my pack.
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T.H | 09. 16. 18
Awesome Jacket. super light and super warm, But doesn't overheat when you get to moving around
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Joe Owens | 01. 20. 18
Love the pattern and the design, very lightweight. But I think the sizing is a bit off. I'm 59", 170 pounds, and the medium fits so tight on my chest I can barely zip it. Also bought the mountain pants, and they are awesome.
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Trevor Trehearne | 12. 26. 17
Really lightweight but very warm nice fit. Except wish it was longer.
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Eric | 12. 24. 17
I want to start this review by saying I had very high expectations for this jacket. From what I had seen in videos and read this was supposed to be the ultimate insulation layer, keeps you warm when stationary, but breathes very well when active. Well upon receiving it the first thing I noticed was how lightweight/thin of a jacket it was this gave me my doubts. Then I had a chance to use it for a late season elk hunt in western Washington. 4 out of 4 stars! This did not disappoint at all! I put it on in the morning and never took it off. It was exactly what I was hoping for, can definitely feel the warmth when you're wearing it and is great under the Thunderhead jacket. I even wore it to sleep in for added warmth. But I never got too hot when wearing it solo or layered. Idk how they did it but it's great. The body is a little short but it was made this way so it isn't sticking out underneath other jackets when used as a layer. I'm 5'8" with athletic build and with Sitka performance fit I wear a large and this fit the same. Great jacket, I highly recommend it.
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SE | 11. 13. 17
Just a regular dude here. The hype is real...Soft, quiet, drys quickly, and is lightweight. Makes a great pillow in the sleeping bag. It's almost like a really intense base layer in the sense that it's warm, but wicks away moisture. It's bizarre; no other jacket like it and I recommend you check it out.
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Jason | 10. 17. 17
Not sure how they do it. I have the Kelvin Lite, the Kelvin Ultra Down, and the Kelvin Active. All excellent pieces and all seem to be designed for something different. I didn't think it could get any better than the Kelvin Lite. Then the Kelvin Ultra Down came out. My absolute favorite piece. Being a little skeptical of their newest piece, the Kelvin Active jacket, I put it to the test. The previous pieces are mostly design for low activity to no activity. The Kelvin Active jacket somehow keeps you warm with low activity and vents heat during high activity without sweating. No clue how they do it but this jacket is a killer at have. Warmth without overheating.
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DS | 09. 26. 17
This jacket is AWESOME! Was super excited about it when I tried it out at the Western Hunt Expo and it lived up to the hype. Wore it for two weeks while guiding wilderness hunts and it is probably my most favorite new piece of gear. Plenty warm as a stand alone outer layer even on cool mornings riding in on horse back and combined with decent rain gear, it's a perfect mid layer. Dries out quick and seems to help keep my base layer dried out as well. Going to be even better during the rifle seasons underneath my Jetstream jacket.
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Jon Sica | 09. 17. 17
This thing is awesome. You can go uphill all day, and never be too hot or too cold. Dries like a dream and makes a great pillow...what more could you ask?
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The Linguists

SITKA Gear | 07.26.2017

Few sounds in nature rival the bugle of a bull elk. Join nine-time World Elk Calling Champion Corey Jacobsen as he explores a hunting legacy with elk calling pioneers Larry D. Jones, Wayne Carlton, Rockie Jacobsen, and Will Primos.

Product Technology


Layering is a science with our CORE system of next-to-skin products. Each of the fabric weights—light, mid, and heavy—wicks away moisture to keep you warm and dry, while Polygiene® technology safely and permanently neutralizes odors using naturally antimicrobial silver salt.