From the Manufacturer
The 890-A wired push button features a antique brass finish and lighted insert. This push button has a portion that must recess into the surface it is mounted to. It requires a 5/8-Inch (or 16mm) diameter hole to be mounted properly. The plate of this push button sits flush on the surface, while the back portion of the push button recesses into the hole.
Heath Zenith 890 Antique Brass Collection, Wired Push Button, Lighted, Antique Brass Heath Zenith is synonymous with quality, integrity and innovation around the globe. They are committed to developing products that enhance their customer's lives through peace of mind, safety and convenience. Heath Zenith has been the leader in innovative and quality products for over 60 years.Heath Zenith 890 Antique Brass Collection, Wired Push Button, Lighted, Antique Brass Features: Antique Brass Finish Lighted Recessed Mount (.625" hole required) 1 Year Warranty 1.25"w x 3.5"h x 1"d