The TGBT4N from Timeguard is an electronic timer that has automatic timed countdown selections for up to 4 hours using a simple pish button, making them completely effortless. The timer is suitable for immersion, heaters, room heaters, towel rails and lighting (not suitable for discharge lighting). The timer features boost times of 1/4 hour, 1/2 hour, 1, 2 and 4 hours. The timer also has and LED indicator to show when the power is on. The timer has normally open contacts and requires a wall box with a minimum depth of 25mm. 3 Year Manufacturer .