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Klim Aggressor Shirt
  • Klim Aggressor Shirt - Black
  • Klim Aggressor Shirt - Black

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Klim Aggressor Shirt

KLIM’s Aggressor Shirt provides the world’s best upper body base layer performance and is the ideal beginning of your truly Intelligent Layering System. Dress right and you’ll experience more comfort in all temperatures. With the world’s best moisture-wicking, breathable, fast-drying and comfortable four-way next-to-skin stretch material, conditions from freezing to hot will be under your control.Low-profile micro-cuffs at the wrist increase comfort, and the high contrast stitching add a technical look. Whatever condition you you ride in, the Aggressor Series ensures you’ll be comfortable and dry ride-after-ride.


  • Contrast stitching
  • Low-profile wrist micro-cuffs enhance comfort and increase mobility
  • Athletic contoured patterning
  • Anti-static comfort control
  • Breathable, moisture-wicking poly/Spandex fabric
  • Anti-microbial and fast-drying
  • Four-way stretch
  • Crew neck
  • Drop down back tail
  • Flat lock stitching
  • Tagless 


We highly recommend finding a cloth tape measure and taking the time to take these measurements.  Klim sizes will not necessarily correlate with fitment in other brands.

Klim Men's Base/Mid Layer Top Sizing:

Size Chest (in) Sleeve Length (in)
XS 32 - 34 24 - 25
SM 35 - 37 26 - 27
MD 38 - 40 28 - 29
LG 41 - 43 30 - 32
XL 44 - 47 33 - 34
2XL 48 - 51 35 - 36
3XL 52 - 55 37 - 38

Sizing information is provided by the manufacturer and does not guarantee a perfect fit.

Click here to see the full Klim Size Chart
Product Style RevZilla Item # Manufacturer Product # Availability
Black / XS 842889 3356-003-110-000 In Stock: Usually ships in 2-3 business days
Black / SM 842890 3356-003-120-000 Out of Stock
Black / MD 842891 3356-003-130-000 Out of Stock
Black / LG 842892 3356-003-140-000 Out of Stock
Black / XL 842893 3356-003-150-000 Out of Stock
Black / 2XL 842894 3356-003-160-000 Out of Stock
Black / 3XL 842895 3356-003-170-000 In Stock: Usually ships in 2-3 business days


Orders $39.99 and over qualify for our fast free shipping offer. Click Here for FREE Shipping Terms and Conditions.

Please see our International Orders page for orders shipping outside the US.

We show real-time availability on this product page when you select the size/color item you want.  Most items will ship the same business day an order is placed,however if an item requires additional processing time a message will be shown indicating such.

See our full Shipping Policy for further details.


If your order arrives and it is not right, we will we'll fix it, NO NONSENSE, we promise.

Doesn't fit or just not happy with it? You can return any new, unused and unaltered item within 30 business days of delivery receipt of your item. We will issue a full refund to your original payment method.

See our full Return Policy for all of the pertinent details.

Write a Product Review for a chance to win our monthly $100 giveaways.
Klim Aggressor Shirt 4.8 5 11 11
Much better than expected Pros: good fit, 75+ speeds on the freeway don't push the sleeves down from the wrist, comfortable, I look better than I should donning it. Cons: Too hot for 80+ temps at slow speeds, too cold by itself riding below 60 degrees, The cons are overstated. Those conditions are not what this shirt is made for. I use it as a morning base layer under my jacket. I really like this shirt, I'm glad I got 3 of them on closeout. I have a 44" chest and the XL fits like a fitted Nike Pro combat shirt. I could blathering on in greater detail but in reviewing what I wrote I think it succinctly states how i feel October 23, 2015
Good base Have not used this enough to make a solid review but first impressions from 50 degrees up are great. Looking for something that works well from 35-55 degrees and think this might be the ticket. It is certainly a well made product that fits well and is sized correctly. Very happy to date.... September 28, 2015
The fit and feel is great This shirt is awesome,much more superior than tranditional thermal underwear, love the fit and feel,its great ! I also purchased the pants, I liked the combo so much my wife wanted me to order her a set, and being the good husband that I'am I did exactly what she ask of me,and when she got her set hugs and kisses for me,and warm comfort for her!! Oh buy the way she also loves her combo. Thanks Revzilla's ,for making a old couple warm again :-) :-) April 5, 2015
Size runs big, but has Klim quality I bought a Medium size (my normal size) but it was a bit loose. It would be OK as a regular undershirt but I prefer baselayers to be snug. I gave it to my son (he's happy!) and ordered a Small for myself. This fits much more snugly and is an ideal baselayer. The quality is typical Klim. The price is OK - it's not inexpensive but it's worth it! March 30, 2015
Excellent price and Quality At nearly half the price of other brands of technical undies, I'm definitely buying more. Waiting for spring to see how they breathe in warmer weather. March 22, 2015
This shirt was a life saver....... I purchased this base layer for my trip to morocco with charley Boorman. I originally just needed it in case we hit colder weather in Africa. Well that was an understatement. Morocco had the worst snowfall in 40 years at the base of the Atlas Mountains. Needless to say I was happy to have this shirt. It kept me dry and warm under my klim overland jacket and was relieved I packed it. March 9, 2015
Typical Klim quality As with all Klim products that I've owned to date, this shirt does as advertised and is another winner. October 27, 2014
KLIM Agressor Shirt I was preparing to ride to the Ohio Spyder Rally and temperatures were predicted to be cool, 40's and 50's. I ordered the Klim Aggressor Shirt to wear under my riding gear as an extra layer. It proved to be all I hoped for. Very comfortable, fit was spot on, and it helped keep me warm, but still wicked away moisture and kept me dry, too. I rode over 1300 miles in five days, in cool, windy weather and stayed comfortable the whole time. October 20, 2014
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Have a functionality, fit, or otherwise product-specific question about the Klim Aggressor Shirt? Ask it here! If you have a customer service or shipping question, please direct it to our Customer Service department.

Klim Aggressor Shirt
Already Asked: 1 Question, 11 Answers
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RevZilla Store asked: Why did you choose this?
Robert M: Clearance price and great reviews as a base layer. Oct 28, 2015
David B: Great base layer that really works. Oct 18, 2015
Bill P: Preparing for cooler weather in the fall and Klim products seem to be the best. Will confirm when it cools off. Sep 11, 2015
Daniel G: Looking for a good base layer that is not too outrageously priced as that is why I spent so much on a good quality adv. riding jacket. I believe Klim provides great value for money and doesn't sacrifice too much on quality. Besides, Klim is da bomb!! Apr 9, 2015
Cindy K: Purchased as a gift for son-in-law who is an avid motorcycle rider, snowmobiler, and snowboarder who has always wanted Klim apparel. Dec 13, 2014
Richard B: warm and dry Nov 10, 2014
Kevin M: Great under garment. Oct 8, 2014
Daniel M: I'm about to go on a 1,000+ mile road trip and wanted some base layering since the weather is getting colder . . . Oct 2, 2014
Chris W: "Brand reputation and customer reviews on wicking capability- needed for two week road trip" Jul 20, 2014
darren a: Already have one , this is my second, wicks away the moisture very well and drys out quickly also. stops the sticky feeling. Apr 13, 2014
Jashan S: Second set of the same pants and shirt (Klim Agressor) that i am getting.
Great quality. Used it for a 7500km trip and washed and re-used multiple times.
Good quality.
Would recommend.
Feb 6, 2014