The main chambers use the Advanced Elements Spring Valve. This valve has the function and durability of other military type valves and is compatible with most standard pumps. The Advanced Elements Spring Valve has a spring loaded plunger for easy inflation and deflation settings. To change from inflate (doesn’t let air out of the chamber) to deflate (doesn’t let air into the chamber) you simply push in with your finger and twist. The other chambers are the Twistlok valves.