This ultra-lightweight pumpbag is made from 20 denier coated nylon with fully taped seams so it is completely waterproof. The base of the bag features the Exped Schnozzel, a small tube with valves that attach to the Exped mattress inflate valves to enable you to quickly & easily inflate your mat. The bag has a roll top closure, just like the Exped dry bags to allow a wide opening to trap air. Simply attach the Schnozzel tube to your mats inflate valve (youll need a flat valve adaptor for mats with an integrated pump), fill the bag with air, roll the down the top & squeeze the air into the mattress, youll need to do this 2 or 3 times depending on the size of your mat. No more puffing & getting dizzy trying to inflate your mat after a hard day out. When youre not using the Pumpbag to inflate your mat it can be used as a compression dry bag for any spare clothing. Stuff the bag with clothes & then roll the top closed, squeeze out the air through the Schnozzel & then close the valve. Ultra lightweight nylon with taped seams Anchor loop for ease of use Can be used as a compression drybag Exped quality construction