With Wireless Doorbell Chime, users mount wireless button next to door and plug receiver into any indoor electrical outlet. No electrical wiring or through-the-wall drilling is required. Wireless Entry Alert® chimes when door is opened, greeting visitors, customers, or clients with sound of music and alerting of their presence. Both units offer 500 ft range between transmitter and receiver. With push of button on transmitter, users can select 1 of 10 sounds.