On demand hot water - no delay. Cut energy waste - Flow switch activates heater only when water is running, no standby heat loss. 99% Efficient, 99 energy factor. Endless hot water - No storage capacity to deplete. Reduces installation cost and material - No T&P valve required (check local codes). Adjustable temperature display from 80 to 140 degrees. Easy Installation - Simple NPT fittings that require no soldering.