They can be fitted surface mounted or into flush fitting boxes with the wall, and are exactly the same size as a standard double 13amp socket.
The 13amp socket version can be fitted at low level with another socket at high level, adjacent to a shelf, for projectors etc.
Plug almost any type of switch into the unit and you can control the equipment in any of the four modes with complete safety.
You can set the mode and times separately, each in a different mode or all at the same setting in one easy step. Once set the control panel can be 'locked' so the setting cannot be changed.