High Compatibility: Our illuminated doorbell button is compatible with low-voltage doorbell systems and is an ideal replacement for most home or garage doorbell switches. It can be mounted on most surfaces, such as plaster, wood, brick, and stone. High-Brightness LED Light: The upgraded LED doorbell button is constantly lit 24 hours a day and powered by low voltage; it provides clear visibility even in the dark, eliminating the need for visitors to search for the doorbell; it 't overheat or burn out like a light bulb. Patented Design: This doorbell button is made of waterproof material; temperature range: -4 to 240 degrees Fahrenheit; an ideal replacement for your old, yellowed, cracked plastic buttons. Important Notes: If you use a digital ringtone (plays a melody; a speaker emits sound), a diode is required (not included); if you use a mechanical doorbell (two sounds; similar to a mallet striking a metal bar), a diode is not required. Color: Black Material: Copper Package Contents: 1 * doorbell 2 * screws 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.