Reduce the space used for your sleeping bag with these Sea To Summit compression sacks 

BEST USE: Pack organization

WATERPROOF? The fabric is waterproof enough for storage inside a pack, but the seams are not tape sealed, and the top does not utilize a roll-top closure. So - water resistant rather than waterproof

SIZE BREAKDOWN: 
S: 10L
M: 14L
L: 20L
XL: 30L