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 3 or 4 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 and 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