The HX-655-SN wired push button features a satin nickel finish with a LED Halo-lighted center push button 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.