300DWSPAL by Dixon Valve | Cam & Groove Coupler for Welding | 3" Coupler Socket Weld x Schedule 40 Pipe | AluminumSafety Notes: Final weld preparation, as with all weld fittings, is the responsibility of the welder. Dixon and Boss Lock cam & groove couplings do not interchange in the 8" size. The 8" Dixon design has 4 cam arms. Under no circumstances should cam and groove couplings be used for compressed air or steam service! Pressure rating recommendations are based on the use of mating Dixon fittings at ambient temperature 70F 21C with a standard seal