This 6" (152mm) Victaulic 300 MasterSealTM Butterfly Valve is constructed of a ductile iron body and disc, a lubricated nitrile rubber seat, and a lever lock handle that may be configured for infinitely variable service with a lockable memory stop. It is designed for pressures ranging from full vacuum to 300psi, and its valve seat design compresses to form a larger seating area as pressure increases, ensuring a full, 360 degree seal. These valves are built to withstand harsh environments for long periods of time, but they should be inspected periodically for corrosion or washed out ball and seat and replaced when needed. Alfa Laval is a trusted distributor of this part and other select Victaulic manufactured components.