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Sender Fast Adjust Harness

4.25 out of 5 stars
4 Reviews

Out of Stock

Don't worry though, we have a lot more Sport Harnesses in stock than that.

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Sender Fast Adjust Harness

The Sender Fast Adjust Harness is Mammut's lightest harness for climbing; in fact, it's so light and packable that most mountaineers would choose it over mountaineering and alpine harnesses. A single self-locking waist buckle and Fast Adjust leg loops ensure quick-and-easy entry and exit whether you're wearing sport climbing attire in the summertime or insulators for high-altitude, freezing climbs. Mammut instilled bright colors in the tie-in loop to indicate when it's time to replace the harness once the bright colors show. 


  • Mammut's lightest harness for climbing and mountaineering
  • Split Webbing with laser-cut mesh for breathability and lightness
  • Self-locking buckle at waist and Fast Adjust leg loops
  • Tie-in indicator lets you know when it's time to replace
  • Two large gear loops at the sides, and two lighter loops behind
  • Attachments for four ice screw carabiners, and chalk bag hanger
  • Item #MAMU51T
single, self-locking
Gear Loops
Ice Clipper Slots
Chalk Bag Hanger
Claimed Weight
Leg Loops
fast adjust
Manufacturer Warranty
2 years

Overall Rating

4.5 based on 4 ratings

Review Summary

1 Stars - 0 reviews
2 Stars - 0 reviews
3 Stars - 0 reviews
4 Stars - 3 reviews
5 Stars - 1 reviews

Fits True To Size

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Runs smallTrue to sizeRuns large

What do you think about this product?


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4 out of 5 stars

September 22, 2023

Comfortable, but not what I wanted

I returned this product before using it
Size Bought:
5' 7"

Caveat, I never actually used this harness outside, I only ordered and then returned it. The harness is well built, very lightweight, and comfortable. That much was obvious from putting it on at home. However two things were a deal breaker for me that I couldn't tell online. First the gear loops are pretty small. For sport climbing this harness would be great, but loading more than a light trad rack for multipitch climbing was way too tight. Second, the leg loops, while adjustable, cannot be undone, they are sewn into a loop that can change size, but cannot be undone (they also were pretty hard to adjust). For winter sports the harness I need to be able to undo the leg loops and waist to put it on over the my layers and boots.

Jack S
5 out of 5 stars

June 27, 2023

Very comfortable and lightweight.

I've put it through the wringer
Size Bought:
5.643045' 67.71654"

I wear this harness 4 days a week and it is very comfortable and lightweight for regular climbing. I would highly recommend this harness for frequent climbing and everyday use.

Robert R
4 out of 5 stars

September 19, 2022

It's a good product. But...

It's a good product. But Backcountry sent me a defective product. There is no big problem using it, but I don't feel good. 1. As shown in the attached photo, I sent the product with cracked plastic surrounding the gear loop. 2. I definitely ordered a new product, but the pouch is contaminated as if you sent me a used product. I want to exchange the product, but it's difficult, so I'm just going to use it.

user image
Heesung H
4 out of 5 stars

June 8, 2022

Super comfortable

I've used it several times
Size Bought:
5' 11"

I love this harness. It’s a huge upgrade in my opinion from my black diamond solution harness. The solution feels super stiff compared to this harness, even with my solution being 2 years old. The front gear loops on this do a great job keeping QuickDraws in a nice front loaded position. My only two complaints are with the tie in loops, and leg adjustment buckles. The tie in loops are really small, and with my PAS and rope attached, it’s pretty crowded. The leg adjustment buckles are difficult to manipulate so I try not to adjust them if I can help it.

Neale S