The main chambers use the Advanced Elements Spring Valve. This is a high-end military style, plunger valve (Push in and twist 90 degrees to activate the spring-loaded check valve for inflating, or push-in and twist to lock open for deflating). You will notice the stem of the valve move outward, or lock inward. When inflating the stem should be in the outward position (or valve closed position). The pump pressure will bypass the closed valve then when you stop pumping no air will come out. The other chambers are the Twistlok valves. Twist open to inflate then simply hold the pump hose on the end of the orange nozzle and pump. When the chamber is full twist closed.