Thank you for viewing! This product is a set of the transmitter and receiver for the "REVEX Wireless Chime X70 X800". I purchased it on Amazon last year and used it for a few months, after which I stored it in a drawer. Operation has been confirmed. The transmitter uses 2 AAA batteries, and the receiver uses 3 AA batteries. (Please note that batteries are not included.) ◉Other: Instant purchase is OK, but please consider this as a used item and understand that. Please feel free to ask if you have any questions!