Feature: 1. Battery Power Supply: Use radio network reception, avoid layout lines, do not pay electricity, use battery power supply (without batteries). 2. Various Ringtones: With 28 chord music and 8 volume levels to meet different ringing needs, make your doorbell more rich and interesting. 3. Easy to Move: Independent base design, can be attached to the wall mounting, reserved holes for drilling, screw fixation or adhesive fixation, easy to move to any place where necessary. 4. Serve the Elderly: The doorbell with LED bright lights, for the disabled elderly, deaf and mute, hearing impaired people. 5. Widely Used: Doorbell can be used in homes, apartments, classrooms, villas, hotels, factories, hospitals and other scenes to meet the needs of multiple scene applications. Specification: Item Type: Cordless Doorbell Product Quality: 220g/7.8oz Receiver: 102 x 67 x 30mm/4 x 2.6 x 1.2in Transmitter: 80 x 50 x 22mm/3.1 x 2 x 0.9in Receiver Power Supply Battery: 3 AA batteries (not included) Transmitter Power Supply Battery: 1 AA battery (not included) Features: 28 chord music and 8 volume levels.. Package List: 1 x Base 1 x Transmitter1 x Instruction1 x Receiver 1 x Small Adhesive 1 x Large Adhesive1 x Slogan4 x Screw4 x Expansion Tube