4 Modes:Sound only, flash only, sound & flash, sound & light on.Light on mode can turn into a night light Memory function:After the power is turned off, the music set .No need to set music again Self-powered doorbell that requires no battery,'t worry if the battery has power, so 't miss important visitors lights, loud ringtones. Especially suitable for the elderly, pregnant women, housewife. Self powered button This button uses kinetic energy.No battery required 4 modes ( features) 1.Sound only 2.Flash only 3.Sound & flash 4.Sound & light on Light on mode can turn into a night light Voltage: AC100-240V Plug Type:EU Plug,it applies to Indonesia, , , , and so on. Receiver :2 Colour:Black Material:plastic Package Contents: 1 * Button 2 * Receiver Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.