The Intermatic EI400 Series Programmable Electronic Countdown In-Wall Timer offers to-the-second accuracy in an auto-off application. Easy installation and simple programming, with options for a visual or audible warning that the timer is about to turn off. You program the amount of time you want the lights to stay on and then a simple push of the button will activate that set time countdown. If you want to turn off the lights before it automatically times out, simply push the button again. Lockable settings help avoid unintended changes to the program. Settings are stored in a non-volatile memory. The timer comes with a replaceable CR2 lithium battery that provides up to three years of operation. No neutral wire connection enables easy retrofitting and quicker installation. Functions to control all voltages 120-277 VAC up to 20 Amps. Single pole or 3-way switch compatible installation. Applications include indoor lighting, outdoor lighting, whole house fans, bathroom fans, spas, garage lights, etc. CSA Certified. 5-year limited warranty. Not for use with sunlamps, saunas or loads that could cause personal injury if timed incorrectly.