It is used in the lighting control circuit with circuit of 50Hz, voltage 220V, to put on or cut off the power automatically. The switch would cut off the power under sufficient light, put on the power automatically according to sound, such as footsteps, claps etc at night or with insufficient light. It would last for 40s-60s every time. It suitable for washroom, stairs or similar place. Specifications: 1) Outline dimension: 87 x 87 x 44mm 2) Voltage of controlled lamp: AC2220V, 50Hz 3) Controlled delay: 40s-60s 4) Controlled distance: 4m 5) Controlled type: head lamp