•Emergency button screwless chuck design, it's waterproof and dustproof even without a rubber ring •Receiver: AC socket, EU plug supports 110-240V voltage •The SOS call button uses a CR2032 battery •SOS button receiving distance: open area receiving distance up to 80 meters •38 Songs to choose from. 4-level volume adjustable (including silent mode) •Easy to use. Just plug the receiver into an outlet, all the seniors/disabled/bedridden need to do is push the panic button to ask for help •It comes with a lanyard, the wearable call button can be hung around the neck, and also can be attached to the walker/chair/bedside Note: •The transmitter shown in the picture is for rendering only (not included). •The wireless signal can be affected by obstacles. The more obstacles, the more serious the loss of signal. Specification: •Call button size: 60x34x11.5mm •Receiver size: 90x56x20mm Package included: •2 x Receivers •2 x Call Buttons •1 x English User Manual •Other things not included