Interchangeable with Sangamo and Horstmann Economy 7 units. Suitable for use with single, dual or twin element immersion heaters. Designed for use with Economy 7 off peak rate overnight electricity plans. 4 Boost demand options - 15, 30 minutes, 1 & 2 hours. 24 hour Segment dial with minimum 15 minute switching intervals. Output LEDs illuminate during off-peak and boost periods. Quartz reserve with 150 hours memory back-up. Fits and supplied with a standard size Economy 7 wall box. IP30 enclosure protection. Class 1 shock protection. Contact rating: 13A suitable for immersion heaters up to 3kW. Operating temperature: 0°C to +35°C. Contact type: Micro-disconnection ON control. Disconnection to immersion heater(s) via double pole rocker switch.