Lightweight InsulationLightweight Insulation


Incredibly ultra-insane.

Phrases like 'incredibly light,' 'ultra-breathable,' and 'insanely packable' get thrown around a lot, but we have a difficult time not using them when describing the Sea To Summit McIII 28 Degree Down Sleeping Bag. Heavy-duty down with feather-light materials keep you warm, while the 2D NanoShell keeps moisture away from the down and lets water vapor escape. The whole toasty package compresses down until it's around 3.5 liters, leaving you lots of room in your pack for some extra caloric goodness.
  • The 850-fill Eastern European goose down gives you superior loft and insulation for a better warmth-to-weight ratio than anything on the planet
  • Breathable 2D NanoShell with Nano DWR uses microscopic water-resistant particles that adhere directly to individual fibers so external moisture is blocked without adding a heavy, suffocating laminate
  • Convertible design means you can leave the foot box open for more room and ventilation then tighten the drawcord to create a mummy-shaped bag when it gets cold
  • Draft tube with lightweight YKK #3 zippers stop heat-loss but add minimal weight, and the micro anti-snag liner protects the soft inner fabric
  • Square, quilted baffle construction won't lose heat at the seams like traditional, sewn-through quilting does, so you don't end up with cold spots

Share your thoughts

Review Summary
1 4
2 3
0 2
0 1

What do you think of the

Sea To Summit McIII Sleeping Bag: 28 Degree Down

? Share a...

Write a review

No file chosen

Rather attach a photo from another website?

Rather attach a photo from your computer?

  • Product review:
  • Share a video
  • Share a photo

How familiar are you with the product?(Optional)

Only jpg, jpeg, png, gif or bmp files please.


Here's what others have to say...

4 5

STS "MCIII" vs. FA Karakorum +20

  • Gender: Male

Have both of these on order and will check both once received. Like the features of the Karakorum +20, but the MCIII really has me on the weight and versatility. Anyone out there have a Karakorum +20 ?

STS "MCIII" vs. FA Karakorum +20

Whats the difference between the MCIII an...

Posted on

Whats the difference between the MCIII an the MCII? Im in alaska would one be better than the other?

Responded on

The Mc III has more down fill, 12oz vs. 9oz, and thus is a warmer bag. I personally would choose the MC III if I lived in Alaska.

5 5

Best bag Ive ever owned

Super light, warm, full side zip, foot box draw closure, works for all temps, can be used as a down quilt. Only issue is really poor sewing on the zipper but it has a warrenty so no big deal!

4 5

Insanium to the cranium

Thios bag got smarts!! This bag is so warm and the fit just snugs to your body!!! So lite and it!

I am 6' even. Would i have to buy the long...

Posted on

I am 6' even. Would i have to buy the long version of this bag in order to have ample foot room with the foot-end pull tie closed?

Responded on

I'm 6', and I always buy the long. Sometimes I can get by with the regular, but the long is always a better choice. That way you can put some of your clothes and a nalgene down in the foot of the bag to help make the morning a little more bearable. Just my 2 cents. Hope that helps!

Responded on

I'll throw in with Brad on this one. I'm 6'-0" and always opt for the long version in any bag. That doesn't necessarily translate into not having enough foot room with a regular, just a preference. However, looking at the radical foot box taper on this bag, as a six footer, I wouldn't even consider anything but a long.