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Sea To Summit Trek TkII Sleeping Bag: 18F Down


Trek TkII Sleeping Bag: 18 Degree Down

The days are getting shorter, but you're not ready to pack up the camping gear and start praying for snow just yet. Whether winter is just around the corner or has just said its farewells, chilly shoulder-season backpacking trips won't be so chilly in the Sea To Summit Trek TkII Sleeping Bag. The 650-fill down insulation will keep you warm on cold nights, whether they find you in the desert or the mountains. And thanks to Sea To Summit's Ultra-Dry Down technology, your down insulation won't lose its loft if you find yourself in wet and cold conditions, or if your bag happens to get wet throughout your travels.

Verrtical baffeling in the chest prevents the down from shifting sideways as you sleep, keeping the warmth where it's most effective and not anywhere else, while a 3D sidewall baffle lets the down loft all the way to the very edge of the bag, ensuring total warmth. A draft collar around the neck and a full length draft tube along the zipper prevent cold temperatures from creeping in, and if you end up wanting some ventilation in the night you've got two-way functionality on the main and footbox zippers. To keep a phone or headlamp close by you've got an internal stash pocket, and to guarantee that your whole body is warm there's an adjustable mummy hood.

  • Warm down bag for cold nights of camping in the spring and fall
  • Hydrophobic down stays warm and dries quickly in damp conditions
  • Draft collar and tube keep warmth inside and cold weather out
  • Vertical chest baffles prevent down migration as you sleep
  • Two way main and footbox zippers allow for easy ventilation
  • Adjustable hood pulls in tight to keep your noggin warm
  • Large internal pockets keeps items close by and batteries warm
  • Included stuff sack lets you pack it down small to take anywhere
  • Item #STS007G

[shell] 30D nylon, [lining] 20D soft touch nylon
650+ fill Ultra-Dry down
full-length, two-way
Max User Height
[regular, regular wide] 6ft, [long] 6ft 4in
Shoulder Circumference
[regular] 60in, [regular wide] 68in, [long] 64in
Hip Circumference
[regular] 57in, [regular wide] 63in, [long] 62in
Foot Circumference
[regular] 40in, [regular wide] 48in, [long] 43in
Draft Tube
yes, neck collar
[internal] 1 stash
Fill Weight
[regular] 18oz, [regular wide] 20oz, [long] 21oz
European Norm Comfort Rating
European Norm Lower Limit Rating
Stuff Sack
Ultra Sil compression bag
Claimed Weight
[regular] 2lb 2oz, [regular wide] 2lb 7oz, [long] 2lb 6oz
Recommended Use
backpacking, weekend camping
Manufacturer Warranty

Tech Specs

What do you think about this product?


>Rating: 5


I've used it several times

I love this bag! I needed a bag for PNW 3 season, colder weather camping (fall, winter, spring). This bag is downright warm within the >30F range even in shorts and a sports bra with heavy condensation due to camping near a river. I slept with it mostly open that night and used it as a side zip quilt. The bag was totally dry and lofty even though my companions older down bag was wet on the outside. I also spilled water all over it (and the inside of the tent--yeah!) and the water beaded off and resisted saturation in time for me to dry it off. In temps below freezing in the 30-25F range, I was super warm in a base layer, workout leggings, and my midweight wool sleeping socks. I actually had to vent sometimes (leg out or unzipped partially). I imagine I could take this bag into its lower range if combined with a down jacket, insulated base layers, and a bag liner. Overall, I am super stoked on this bag for its weight, compressibility (roughly the size of a football at its widest but it a bit longer), price, and water resistance.

>Rating: 4

Snug as a Bug

STS continues to impress. Very happy with this bag. I have used a different bag from STS with a higher down fill which packed a tiny bit smaller than this, but for a 18 degree with only being 650 fill, packed very well for my hike in to the camp spot. Definitely wasn't needing any extra liner to boost the warmth for this bag camping in October in the Uintas. Very pleased and highly recommend!


Hello So I live in the Pacific Northwest and I plan on doing some high altitude late season backpacking trips, im curious about the water resistance of this bag and then how well it can keep the warmth when damp.