No Batteries Needed Press the button and the kinetic energy is converted into electrical energy. Don't worry about running out of battery
Type A parameters:
Volume: 3 files (variable) 0-85db
Ringtone: 60
Transmitter size: 75X51X20MM
Receiver size: 95X65X24MM
Receiver rated voltage: AC 110V-220V-2420
Type B parameters:
Specification
-- Receiver size: 95 x 65mm
-- Button size: 74 x 40mm
--Input voltage: AC110 ~ 240V, 50 / 60hz
--Volume: 0-110DB
--Melody: 60PCs