The doorbell button can't use separately, it works well with home alarm security system.One button simple design and touch press, easy to operate.Most important, improve working efficiency,Save labour cost,Improve service image. How we use the wireless calling system:First, the calling buttons are pasted or put or on the table, when the guest have any service, he or she press the calling buttons, the receiver (LED screen or watch pager) will get signal with vibration or sound, showing the table number, then the waiter will know which table to be served. Transmitting power:+13dBm Frequency:433.92MHz Battery:CR2032 Cell Battery (included) Tips: The product may be updated constantly ,Due To Different Batches, The Actual Product May Have Slight Differences Or Color Differences, Which Does Not Affect Use Colour:Blue Material:ABS Package Contents: 1 x Wireless Doorbell Button 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 picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.