Professional Classic® Series Rheem RTEX-04 energy efficient tankless electric indoor inline water heaters offer continuous/endless hot water quickly and on demand for single point-of-use sinks, showers or bathroom or multiple applications. These compact tankless residential electric water hot heaters are also great RVs, campers, mobile homes and travel trailers. Rheem's compact low profile design allow these small, yet highly powerful, eco freindly and money saving 0.9 gallon per minute point of use tankless water heaters to fit easily under kitchen and bathroom sinks and counters.