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Klim Aggressor Brief
  • Klim Aggressor Brief - Black
  • Klim Aggressor Brief - Black

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Klim Aggressor Brief

KLIM’s Aggressor Brief is the most comfortable, non-padded riding short KLIM has ever created. Utilizing the same moisture-wicking, breathable, fast drying and ultra-comfortable four-way stretch material as the Aggressor Shirt and Aggressor Pant, this low-profile short will soon be your favorite riding brief for all temperatures and all rides. Choose your next-to-skin layer intelligently and you’ll be drier and ready for more miles every time.


  • Contrast stitching
  • Patterning removes in-seam seam for ultimate riding comfort
  • Athletic contoured patterning
  • Anti-static comfort control
  • Breathable, moisture- wicking poly/Spandex fabric
  • Anti-microbial and fast-drying
  • Four-way stretch
  • Non-abrasive elastic comfort waist
  • Flat lock stitching
  • Tagless
  • Front fly


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 Pant Sizing:

Size Waist (in) Inseam (in)
XS 29 - 31 29
SM 32 - 34 30
MD 35 - 37 31
LG 38 - 40 32
XL 41 - 43 33
2XL 44 - 47 33
3XL 48 - 51 33

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 842903 3358-003-110-000 In Stock: Ships next business day
Black / SM 842904 3358-003-120-000 Out of Stock
Black / MD 842905 3358-003-130-000 Out of Stock
Black / LG 842906 3358-003-140-000 Out of Stock
Black / XL 842907 3358-003-150-000 Out of Stock
Black / 2XL 842908 3358-003-160-000 Out of Stock
Black / 3XL 842909 3358-003-170-000 Out of Stock


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 Brief 4.8 5 15 15
Pleasantly surprised Been looking at some other brands for a while, needed to find some relief for my seat. Found these on ZLA and decided to try them out since they were half price of the heavily advertised brand. Fit was good based on recommendations and on a 2-day trip there was a noticeable improvement compared to all other shorts/underwear I've tried. Will definitely buy another pair. October 3, 2015
Ok for short rides I own a lot of Klim gear and most of it is first rate. However this particular piece of clothing is not typical Klim quality nor do they work very well. Although the shorts appear to be well made they ride up, on me at least. They end up bunched and are really uncomfortable on longer rides. They need to be longer in the legs. In addition the material does not seem to breathe particularly well, consequently they are hot especially in the heat of an early Arizona Summer day. May 4, 2015
All day riding Great fit and they breath really well. Washout and dry overnight. Solid waist band and the crotch area is very accommodating. April 2, 2015
More comfortable than they look When I unpacked these, I thought the seams would be giving me grief after a day of riding, but no. Fit me well and didn't bunch up or stick and no pressure from seams, I think I'll buy some more! March 2, 2015
Comfortable riding garment These briefs are very comfortable and breath well. October 27, 2014
Great product! I've been using these for a few months and have zero complaints the fit & feel is great. No bunching, breathes well. September 12, 2014
Comfy and dry Keeps me dry and are comfortable. No bunching up either. Nice true fit I would recommend this product. September 1, 2014
No comprimise.. pure comfort Klim Agressor is the best short I've ever used. I definitely recommend this product for adventurers. It's elastic, breathable and fits well. August 20, 2014
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Have a functionality, fit, or otherwise product-specific question about the Klim Aggressor Brief? Ask it here! If you have a customer service or shipping question, please direct it to our Customer Service department.

Klim Aggressor Brief
Already Asked: 3 Questions, 29 Answers
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RevZilla Store asked: Why did you choose this?
Stephen H: why choose anything else Nov 27, 2015
Gary W: because of sale price and I do not have any riding brief. and the price is worth a try Sep 24, 2015
Kevin M: More comfort, breathable, wicking, no seams. Sep 19, 2015
Ken B: These are fine and all for those days when you get hot and bothered and want to stay cool but if you're used to wearing boxers these will feel odd; and they really like to help your pants slide off if they're not fastened properly. Apr 2, 2015
Vincent V: good reviews, fairly priced. Worth a buy to see if this product can fit my needs as I am doing a lot of riding this year. Mar 18, 2015
Ryan B: Have purchased them in the past and they work great. You don't know what you are missing until you try them. Feb 8, 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
D A: I have a pair of LD underwear, which I find are too tight. These are excellent. I tested them against LDs, my regular Duluth 'Naked' boxers and another pair last weekend. They came out on top as the most comfortable by far. Nov 3, 2014
Kevin M: Not my best purchase. Oct 8, 2014
S T: Thought I'd try something other than cotton underwear to see if it made that much difference on a mid to long ride. Sep 27, 2014
William H: Riding to Big Bend, Texas in July. Needed comfort for long ride in hot weather. Sep 10, 2014
Chris W: Brand reputation and customer reviews on wicking capability- needed for two week road trip Jul 20, 2014
Scott L: Good user reviews from other customers. Jun 23, 2014
Andy F: There comfortable and last a long time. Jun 14, 2014
Lukas v: Worked great in 108'F weather. Very comfortable. Jun 2, 2014
Jeff S: All the briefs rated well, but these had a front fly. May 23, 2014
Stacy T: the seams in the crotch drive me crazy. LDcomfort shorts work better. These are just cluttering my sock drawer. May 8, 2014
darren a: 2nd pair , very comfortable and seem to help with the monkey butt Apr 13, 2014
JOHN R: The seams on my tighty whities were killing me! Jan 12, 2014
Jim M: Comfortable and will dry over night when I wash em out at the end of a day. Sep 9, 2013
John R: Long range comfort and Klim reputation for quality. Sep 9, 2013
David C asked: Which size would I get with a 34" waist? May 24, 2014
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Gail B: I have a 34 waist and wear the Medium. Just a note, I have a slim legs. May 24, 2014
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Jeffrey A: Medium fits

32-35" waste
156-186 lbs
May 24, 2014
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darren a: Medium Jul 9, 2014
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J C: Large. May 24, 2014
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A shopper asked: Are they true to size? if so, what is Klim size chart? Mar 22, 2014
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Ryan B: I ordered the same size that I wear in similar style Haynes underwear. They fit as they should. May 15, 2014
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michael l: Yes I am a 36 to 38 pant and a large is fine Mar 23, 2014
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Gordon M: Yes they are true to size. I have a 33" waist and medium fits perfect. I am not sure on the Klim size chart sizes. Mar 25, 2014
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JOHN R: They fit spot on! Apr 1, 2014
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