This AC WORKS brand inlet wiring device is a heavy-duty power input connection device with weather cover. L15-20 Inlet is used for an industrial and commercial grade flange inlet. This inlet works with a 12 AWG (American Wire Gauge) or above copper wire and is commonly used for residential, transfer switch, cabins and generator power. Note: 18-Gauge is for 10 Amp, 16-Gauge is for 13 Amp, 14-Gauge is for 16 Amp, 12-Gauge is for 20 Amp and 10-Gauge is for 30 Amp. California Residents: See Proposition 65 Information Industrial, Generator, Transfer Switch and Cabin Power Inlet 3-Phase 20 Amp, 250-Volt Inlet NEMA L15-20P 3-Phase 250Volt Power Inlet UL and C-UL Certified 1-year Limited Warranty.