3-1/2" ( 90mm ) Diameter Clock Insert Fit-up Unitwith brass color plastic bezel. Plastic clear lens. Elegant metal Roman dial with fancy gold center. Quartz unit, very nice quality, attractive and affordable. Holds into a 3" dia. hole or 3-1/8" dia. hole. Supplied with rubber ring to fit 3-1/8" diameter hole. Dial/Hands/Clock all in one unit.Simply insert into hole.Premium design back time set knob. Requires one AA battery-not included. Overall Diameter: 3-1/2 inches. Mounting Diameter: 3 inches - 3-1/8" Minimum Mounting Depth: 5/8 inches, though best to drill hole clear throughfor easiest access.