The GG Drylite Rock Solid Compression Sack sounds like it will keep my down sleeping bag dry and small. I have a BA Lost Ranger Regular. What size should I get? The stuff sack it came with is 8" x 17.5".

Tech Specs:

Material:

PU Coated nylon ripstop 

Volume:

[S] 600cu in, [M] 900cu in, [L] 1200cu in, [XL] 1600cu in 

Dimensions:

(Diameter/Height) [S] 6.5/16.5in, [M] 8/18.5in, [L] 9/20in, [XL] 10/21in 

Pockets:

None 

Compression Method:

Nylon webbing/buckle system avoids bulges 

Weight:

[S] 4.1oz, [M] 4.5oz, [L] 5.7oz, [XL] 6.2oz 

Warranty:

Lifetime 

Country of Origin:

China