Watchguard Ceiling Mount Wireless PIR Motion Sensor
This wireless PIR sensor can be mounted on the ceiling of the room you want covered and will give you full 360 protection for a 6m range on ceilings up to 3.6m high. This unit uses dual-core infrared processing technology to prevent false alarms. The PIR sensor runs of 2x AA batteries and will let you know when they need replacing. Comes with a 12 month warranty.