True Union design permits installation or repairs without expanding pipeline. Valve,Diaphrgm,1",PVC,Socket Bubble-tight sealing, even in applications such as slurries or suspended particles. Uniquely designed body and bonnet together with diaphragms of new sealing designs by the state-of-the-art computer aided analysis for superior sealing. Rugged square body and bonnet are of solid thermoplastic for maximum corrosion resistance.