The EI400 series provides more specification flexibility, ease of installation and absolutely silent operation. A factory supplied CR2 lithium battery provides up to three years of time keeping without AC power and user program selection is stored in non-volatile memory. A low battery indicator appears in the display when the battery requires replacement. A field selectable warning feature provides an audible and/or visual signal that the load is about to switch off. Functions to control all voltages and frequencies (within the contact ratings) with no adjustments required. Provides "true" 3-way control allowing the load interval to be started and stopped using a standard mechanical switch. Switch ratings - Resistive (heater): 20 amp, 120-277 VAC; Tungsten (incandescent): 15 amp, 120 VAC; 6 amp, 208-277 VAC; Ballast (fluorescent): 16 amp, 120-277 VAC . Not for use with sunlamps, saunas, etc.