G'day Jak,

I assume you're referring to the difference between the in use and packed dimensions on our site? If so, the packed dimensions refer to the sack in it's packaging as displayed in the final photo. The in-use diameter will remain the same with the length decreasing as you compress the sack. 

G'day Floyd,

Sea to Summit recommend the Medium Compression Dry Sack for the Trek III sleeping bag.

G'day Sue,

Sea to Summit classifies the Altitude ATII as fitting into their Medium size dry sacks, which are the 4.5L-14L size.

G'day Catherine,

You'll find the capacity in litres and the compressed volume for each size listed in the specifications list within the Details and Specs drop-down tab. 

G'day Jenny,

The Sea to Summit Talus WTSII Sleeping Bag packs down to around 7.1L when compressed. I'd recommend using the Medium Sea to Summit Compression Dry Sack because it starts at 14L and compresses down to about 4.5L.

G'day Jack, 

Normally we'd recommend someone pops into the store to give it a try but I'm not sure that'll work in your situation. I'd probably recommend the Medium Sea to Summit Compression Dry Sack. A compression sack can always be made smaller but it can't be made any bigger, plus if there's ever any excess room then you can always add your thermals or pillow in the back to compress as well. 

G'day Bill,

Whilst using a Sea to Summit Compression Dry Sack on your tent shouldn't damage it at all, I doubt that it will compress it much more than you'd usually expect from just rolling it up. 

G'day Fiona,

A high quality vinyl bag is going to be quite durable and abrasion resistant, and in general they’re made for taking with you out on the water for kayaking etc.

The compression dry sack is designed more to go inside your pack, and keep your gear completely dry and compressed - so it may be slightly less durable than something that’s designed to be out in the open where it’s going to get roughed around.