LIGHTED: the built in light makes finding the doorbell a breeze, especially in darker settings SPECS: total length: 2.85"; distance between screw holes: 2.09" SURFACE MOUNT: this doorbell push button can be easily installed on almost any wall or flat surface area MAXIMUM VOLTAGE: when installing and using this lighted push button doorbell, do not exceed 16 volts WARRANTY: this push doorbell button is guaranteed with a 1-year limited manufacturer's warranty