The Rheem RTEX – 08 is tankless electric water heaters offer continuous hot water quick and on demand for single point-of-use or multiple applications. For easy use it has an e xternal adjustable digital thermostatic control with LED display. The controller increments at 1F ranging from 80F to 140F. The Rheem RTEX 8 is the replacement model for the Rheem RTE 9.