The CRL Chrome Track Plunger Lock installs easily on sliding glass doors with track assembly. It can be installed at the top or bottom of the door. The spring-activated design permits locking by pushing the plunger without using a key. Comes with lock, ferrule, and two keys. If the 981 Lock is used with H-Bar Shoe Cat. No.'s D610, D5610 or MC610, the glass will require notching. If the LK610 H-Bar Shoe is used, no notching of the glass is required. Requires 5/8 inch (16 mm) diameter barrel hole and 3/8 inch (10 millimeter) diameter ferrule hole.