This bi-fold closet door top guide wheel is constructed of a plastic wheel and base, with a steel shaft and spring. The outside diameter of the wheel measures 7/8 inches, and the base diameter measures 3/8 inches by 1 inch in height. This assembly features a spring-loaded action to ensure the wheel rolls consistently within the bi-fold track above the doors. This bi-fold closet door top guide wheel assembly is used by Acme, Stanley, Kenna Frame and other bi-fold door manufacturers.