Wireless ringing without batteriesi

Wireless doorbell system whose external push-button is powered by the pulsation itself instead of a replaceable battery; the exact model and energy capture mechanism are not confirmed. Technical Data: The user indicates that the external pushbutton works without batteries. Neither the exact marking and model nor whether the mechanism is piezoelectric or other electromechanical generator are confirmed. Context: You can avoid the use of disposable or rechargeable batteries and wiring on the external push-button; the real benefit depends on the durability and design of the product.