Use this Prime-Line U 9980 Aluminum Sliding Window Security Lock to secure metal horizontal sliding windows in a closed or ventilating position. The thumb turn screw of this sliding window lock secures the lock in place. Easily install this secondary lock with no tools required. The secure window lock has a natural finish and can fit up to a 1/8 inch wide rail. For further dimensional information, please see the line drawing and compare with your needs before purchasing