All sensors that fit on door or window frames, as well as the PIR movement detectors, are wireless. They use long-life Lithium-Ion batteries that will last for up to two years. The external siren is also wireless and again uses long-life batteries to ensure you have an easy, wire-free installation.
The central hub requires a standard 240v plug for power and also employs a battery providing 12 hours of continuous backup should the power fail. It is, of course, possible to provide mains power to the unit directly from a cable within the wall. It is a requirement to meet a grade II level specification that the central hub uses mains power and has a battery backup. The unit will also have the ability to detect if mains power is cut deliberately or through a power failure.