This AC WORKS brand inlet wiring device [ASINL520PFC] is a heavy-duty power input connection device with weather cover. It is used for an industrial and commercial grade flange inlet. This inlet works with 12 AWG (American Wire Gauge) copper wire and is commonly used for boats, RV's and small trailers, cabins, residential, transfer switch 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. California Residents: See Proposition 65 Information Residential, Generator, Transfer Switch and Cabin Power Inlet 20 Amp, 125-Volt Inlet with Weather Cover NEMA L5-20P Power Inlet UL and C-UL Certified 1-Year Limited Warranty.