The doorbell is suitable for use in homes, offices, hospitals, factories, restaurants, villas, hotels, schools, and apartments. 300-meter receiving range in open areas. Stable performance ensures reliable operation. Do not mount the button on metal doors, as this may interfere with signal transmission. Simply plug the receiver into a standard electrical outlet. The transmitter can be mounted on the door using the included double-sided tape. Type: US Plug – compatible with countries including Canada, India, Japan, Mexico, Thailand, the United States, and the Philippines. Product Name: CACAZI Category: Wireless Doorbells Power Source: AC (receiver), Battery (transmitter) Remote Range: 300 meters in open area Waterproof Rating: IP44 Transmitter Power Supply: 12V 23A alkaline battery (not included) Ringtones: 36 options Receiver Rated Voltage: 110–220 V Volume Control: 4 levels (20–85 dB) Operating Temperature: –30°C to +70°C Color: Black Material: Plastic Dimensions: Transmitter: 77 × 46 × 20 mm Receiver: 95 × 65 × 24 mm Package Includes: 1 × Doorbell Transmitter 1 × Doorbell Receiver 1 × Double-Sided Tape 1 × 12V 23A Alkaline Battery 1 × Screw