Mostly vintage materials; brass, steel, and electrical meters. Displays AC line current and voltage when in use. Rated max current 4.2A. Use 3 conductor socket.
You can charge up to 4 devices at the same time by plugging them into the USB ports at the top of the unit. The charger is a UL-listed commercial unit designed to be installed in any wall socket. To ensure safety, the artist used the 3rd wire ground as would a conventional USB charger.
When plugged in and in use, the ammeter on the left displays AC current and the voltmeter on the right displays AC line voltage. Most devices use little charging current, so the ammeter does not move very much with only one device connected.
Most of the components are from local vintage stores. The top plate with the charging ports is a drawer handle backplate found at the antique flea market in Lambertville, NJ. The cylinder is part of an old bowling trophy. The base is a tall candlestick holder. The meters are housed in lamp canisters found in Asbury Park, NJ.