style 772 Grinnell Grooved Coupling 
It is capable of pressures up to 750 psi (51,7 bar) depending on pipe size and wall thickness. The Figure 772 Grooved Rigid Coupling is UL Listed for grounding and bonding; it is suitable for bonding systems with a maximum service entrance capacity of 200 amps.
Ductile iron conforming to ASTM A 536, Grade 65-45-12
4" avaliable in Tampa Stock