With an unparalleled 150m wireless range and strong signal penetration, the doorbell reliably alerts you when someone knocks on your door. Four adjustable volume levels and 38 melodies cater to your various needs. The flashing indicator light provides a visual reminder (perfect for the elderly and hearing impaired). The replaceable 12V 23A battery has an ultra-long lifespan of up to 3 years, saving you the hassle of frequent battery purchases and replacements. (Batteries must be provided by the customer.) The wireless doorbell has an IP44 rating for dust and water resistance, making it suitable for use in bad weather and adaptable to almost any outdoor environment. Simply plug the receiver into a standard electrical outlet and then attach the transmitter to an exterior wall with the included screws or adhesive strips. Package contents: one doorbell transmitter, one receiver, one double-sided adhesive strip, and an instruction manual.