A timer light switch is a device that is designed to automatically turn on or off lights or other electrical devices at specific times. These switches have a built-in timer that can be set to turn the lights on or off at predetermined intervals, which can help to save energy and reduce electricity costs.

Timer light switches can be programmed to turn the lights on and off at specific times of the day, such as during the evening when it starts to get dark, or in the morning when it starts to get light.

Timer light switches are more commonly used in homes and businesses as they can be useful for controlling outdoor lighting, such as security lights. They can also be used for indoor lighting when lights are needed at specific times.