Victaulic® FireLock NXT™ Preaction System Check Valve, Series: 769N, 3 in Nominal, Grooved, 300 psi Maximum, Specifications Met: ASTM A536, cULus Listed, Media: Water, Single Interlock Pneumatic Actuator, Ductile Iron Body, Nitrile Bushing/Seat O-Ring, 3-1/2 in OD x 35-3/4 in H