The Intermatic Water Heater Timer Mechanical Switch Auto Voltage 24Hour DPDT Grey controls electric water heaters. This Intermatic timer can be programmed daily be set with trippers from 1 to 23 hours and includes a battery backup. Utilities in many areas of the country offer two electric rates for residential or commercial customers. One rate has the regular daytime electrical rate, the other is the "offpeak" rate. The "offpeak" rate provides customers with "lowerpriced" electricity during the nighttime and weekend periods. These time switches allow the customer to shift electricity use into these "offpeak" time periods in an attempt to save utility costs.