Valken Ultra Rig Low Pressure Output Tank Kit (150psi) Replacement Loader Parts While existing designs may require Speedfeeds While existing designs may require a low force to open the exhaust valve they are still bound by the need to overcome blowback using the speed and mass of the bolt which means that the valve has to be opened with a greater speed than is actually required 4v Small Stick LiPo recommended (Battery not included) the Valken Ultra Rig accepts input pressures up to 800psi allowing its use with most popular and widely available paintball style HPA systems Build your HPA powered airsoft gun for optimum performance