Abstract: A valve controls the flow of an inflation substance such as carbon dioxide from a pressurized container when the valve is actuated. The valve comprises a valve body having an inflow bore, inlet conduit, chamber, interior chamber and interior passage connected to each other and with the pressurized container. The valve is connected to an inflatable apparatus such as an emergency slide or raft by an outlet conduit connected to the valve body and with the interior passage. The valve is closed by a piston assembly which is balanced. The piston assembly includes a guidance collar and a first piston rod connected to the guidance collar. The first piston rod has an O-ring seal, and the piston rod is attached to the valve body by a fitting. The second end of the piston rod extends through the piston fitting and has a valve actuation receiving means.