Intermatic makes plug-in timers for lamps and low-voltage timers for exterior landscape lighting. The company also makes mechanical timers for items such as pool pumps, water heaters and sprinkler systems. Each timer uses either plastic or metal trippers to tell the timer when to turn an item on and off. Depending on the timer, it could have two sets of trippers giving you the ability to turn an item off and on twice during a 24-hour period, or just one set of trippers to activate the timer only once during 24 hours.
Slide a black tripper over the number that represents the time on the dial that you want to turn on the lights.
Insert a red tripper over the number that represents the time you want to turn off the lights.
Install an additional set of plastic trippers over the numbers on the timer dial representing a second on and off time for your lights, if you have a 24-hour timer. Push down on the timers until they snap into place.
Look on the front of the metal trippers to find the one identified as "Off" and the one labeled "On."
Loosen the screws on the face of the metal trippers. Do not remove the screws from the trippers.
Slide the "On" tripper over the time on the dial you want the timer to start operating the appliance or light to which it connects. Tighten the screw to hold the "On" tripper to the dial. Use the same steps to install the "Off" tripper on the dial, over the time you want the timer to turn off the appliance or light.