Mommys Helper patented bi-fold lock is designed to help prevent children from opening bi-fold doors, and minimize the risk of pinched fingers. Features: Improved Design: Easy to use slide rod means less reaching!Clear plastic design blends well with any decorNo tools requiredThe 6 7/8" length of the Slide-Lok extends far enough past the Bi-fold door joint to help prevent damage to the doorsAdjustable to fit any door.includes universal shim.