EASY TO INSTALL: Includes 2 transmitters, 4 screws, 4 dowels, 1 key, and 2 double-sided adhesive strips for wireless wall mounting. EXTRA LONG WIRELESS SIGNAL RANGE: Up to 400 meters (1,300 feet) in open areas without interference from household electronic devices. Ensures reliable detection of visitors even when you are on another floor or in a distant room. 52 CHIME OPTIONS: Equipped with a 40mm stereo speaker that delivers clear and rich sound. Offers 52 selectable melodies and 5 adjustable volume levels, with a maximum output of 115 dB. Assign different ringtones to each transmitter to identify which doorbell is activated. HIGH PERFORMANCE TRANSMITTER: Features low power consumption and is powered by a CR2032 lithium battery, lasting up to 3 years. Designed with IP55 rating for dust and water resistance. Operates reliably in temperatures ranging from -20°C to 60°C, suitable for harsh weather conditions. MEMORY FUNCTION: Automatically retains the last selected chime and volume settings after power interruptions, eliminating the need for reconfiguration. Provides a seamless and user-friendly experience.