Expansion Joint, Bolt Circle Diameter 3 1/2 in, Bolt Hole Size 0.63 in, Bolt Hole Threading Unthreaded, Burst Pressure 853 psi, Compression Distance 1/2 in, Connection Type Flanged, Expansion Joint Type Double Bulb, Features Absorbs Water Pulsation and Minimizes Water Hammering, Applicable for Suction and Delivery (Discharge), Designed for Greater Compression, Elongation, and Angular Movement than the Single Sphere Expansion Joint, Flange Diameter 4 5/8 in, Flange Material Steel