Walking detector alarm, communication range up to 100m (distance between infra-red receivers and receiver). Infra-red receiver range is 3-7m. Warn you in advance when guests (or intruders) arrive. Motion detector alarm with 38 ringtones, you can choose the one(s) you prefer! 3 levels of volume adjustment: High or Medium or Low. Receiver mode of operation: only LED Light flashing or both sound and LED flashing. Power supply (receiver): AC 110-240V. Power supply (transmitter): 3 x 1.5V AAA batteries (not included) or 5 V DC adapters (not included) Applications: Entry Alert, Intruder Alarm, Corridor Alarm, Bug Detector, Car Alarm (Indoor), Warehouse Monitor, Power Closet Alarm, Garage and Tool Shed Monitor, Mailbox, Door 'hall or gateway detection. Features: