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The warmest, lightest bag offered by Sea To Summit brings versatile comfort to your serious summer treks.

Thanks to its highly breathable, water-resistant design, the 36-degree down Sea To Summit McII Sleeping Bag provides lofty, three-season warmth in a small, lightweight package. While compressed, this convertible mummy is the size of a small stove, but when unpacked, its 2D NanoShell and Nano DWR tech uses tiny water-resistant particles to prevent condensation and water vapor from accumulating in the down.
  • Rated down to 36F, this bag is best suited for three-season, warm-weather backpacking and trekking
  • 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 ventilation and then tighten the drawcord to create a mummy-shaped bag when it gets cold
  • Box quilted baffle construction, and a 55 top / 45 bottom fill ratio prevents cold spots at the seams and against the ground
  • Draft tube with lightweight YKK #3 zippers stop heat loss and only add minimal weight
  • Insulated hood adjusts with drawcords to seal in your body heat during chilly summer nights
  • Large internal zippered pocket holds your headlamp close so you don't lose it in the middle of the night
  • Includes a compression sack, mesh storage sack to preserve loft, and a laundry bag for safe washing once back home

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Sea To Summit McII Sleeping Bag: 36 Degree Down

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Here's what others have to say...

Unanswered Question

McII or McIII:
Which would be better for...

McII or McIII:
Which would be better for 3 season conditions, and the occasional winter hut trip. I would most likely be wearing layers.

5 5

Ready, set, go...

Just got it in the mail. LOVE the lightness and its compression down to the size of a Nalgene bottle. I have switched to a smaller, lighter backpack and this bag being compressed so small really helps. I also like the storage bag and washing bag that comes with it. But the big question will be answered when I get out on the AT in Aug. Going from Newfound Gap back to Fontana Dam. Will let you know how it holds up in the real world. If this sucker keeps me warm I'll make all my hiking buddies get one!

5 5

A Ultra light Backcountry blanket/bag!?

I had to buy a long as it was the only left zip in stock... so I might exchange it. But this is a great spring/summer/fall bag. It unzips and turns into a blanket :)... or just un-cinch the bottom and walk around with it on cold night of star gazing. This feature also makes it perfect for pairing it ;).

McII or Marmot Atom?
i need a lot of leg...

McII or Marmot Atom?
i need a lot of leg space + need to be able to put my feet out of the blanket so i'm thinking about the McII.

but i find practically no review online...


Responded on

A little late but MCII all the way! If you're still looking I just posted a review. Any more questions let me know!