The ARISTON GL heaters are NOT tankless water heaters.
The GL2.5, GL4.0 and GL6+ heaters are small tank heaters with the numbers in their part number signifing their capacity in gallons. This is not a GPM rating. All three heaters use a 120 volt 1500 watt electric element to heat the water. Thus all the heaters will draw about 12.5 amps. All the heaters come with about a 3 foot long cord and plug. Globaltowne does sell a GFCI extension cord for use with the GL series if the 3 feet is not long enough.
The GL series is excellent for stand alone sinks. Also it can be used inline with a tankless heater or tank heater to provide instant hot water at a shower while waiting for the hot water to "arrive" from the main heater.