Excellent for any sliding glass door, the CRL Sliding Glass Door Keymatic Plunger Lock is installed directly onto the glass with plunger resting against edge of back sliding door. A 1-1/4" (32 mm) hole must be drilled in the front sliding door to accept the Lock. Will work in doors up to 1/2" (12 mm) thick. A captive operation system allows the key to be removed only in the locked position. Package include the glass cover plate, rubber rings, plastic insert washer and four screws. Additional selections of CRL Keymatic Locks and instructions on keys and combinations are available.