This is a mains powered weather and dust proof (rated to IP55) switch, with a light sensor built into it.
The switch can be used to control lighting so that it automatically comes on at dusk. There are various settings that allow you to adjust the time that the lighting is on for. So, you can have dusk until dawn, or you can set it for 2 , 4, 6 or 8 hours after dusk. This makes the switch ideal for garden, out-building or commercial uses.
The light sensor switch is housed in a tough polycarbonate box, sealed against water and which has a high impact resistance. It is designed for outside use and will not crack or fade. The box has entry seals for cabling at the rear.
The unit comes with full instructions, however it is recommended that if the work is not carried out by a qualified electrician, it should be checked by one.