Revex Sound & Shock Sensor Chime System This is a set of transmitter XP60 and receiver XP700. By attaching the sensor part of this device to your home intercom receiver with double-sided tape, you can be alerted to visitors with sound and light in a separate room. I have used it for several months. There are no operational problems. This listing includes the transmitter, receiver, mounting plate, and instruction manual. Other items such as double-sided tape and mounting screws are not included. Please prepare two AAA alkaline batteries for the transmitter and three AA alkaline batteries for the receiver. This is a used item. Please refrain from purchasing if you are concerned about marks from tape removal, etc.