This is the insert diameter of the opening that the clock fits in You can use this clock insert to make clock Movement Clock Insert has a rubber band gasket to securely hold the clock face in place Appearance: The insert clock features smooth and gold bezel with exquisite workmanship The craft clock insert is designed with black roman numerals marking on the white plate for easy reading This clock is your good to make or use it as a nice for home, kitchen Compatible clock: Miniature clock fitup Insert replacement fits in many types of small glass and crystal clocks movement Great for or replacing old clock faces