Plate measures around 2" diameter. I measured 1.943". Premium Mil. Spec. Switchcraft mono jack with silver plated contacts is installed. The contact integrity and longevity of this jack is 'state of the art'. We include three nickel plated steel mounting screws as depicted. This assembly is the real deal; the best 1/4" speaker input jack you can buy. Usually fitted to the back of a guitar or bass speaker cabinet through a 1&5/16" bore hole. I use a 7/64" drill bit to make the three screw holes.