Triple pole, Four wire, Fusiable Mechanical Interlock Receptacle. 3amp, 440 vac. 30A 3P 4W 380/440VAC FUS MECH INT Legrand-Pass & Seymour http://www.legrand.us/product-detail/PassAndSeymour/IEC-309-Products/Fusible-NonFusibleMechanicalInterlock/Fusible-Mechanical-Interlock/30-Amp/PS430FMIR3W.pdf