The SLP-335 is a 2U high 19" rack mount (220 Volt 30 amp three phase) power distribution bar. This model has a NEMA L21-30 for a Main Inlet connector. There are four 20 Amp independent circuit breakers on the front panel, each of which are connected to one of the three phases ( X, Y & Z ) of the main power inlet connector. The X2 & Y2 Phase breakers distribute power to a split T-slot duplex U-ground receptacle located on the rear panel and Y1 & Z1 distribute power to a split T-slot duplex U-ground receptacle located on the rear panel which is also parallel connected to a split T-slot duplex U-ground convenience receptacle located on the front panel. In addition there are three NEMA L5-30 single twist-lock 120 Volt, 30 Amp outlet connectors located on the rear panel. Each of these are directly connected to one of the three ( X, Y & Z ) phases of the L21-30 Main Inlet connector.