This sliding window lock is constructed of diecast and comes in a white painted finish. This lock is DESIGNED FOR USE ON HORIZONTAL VINYL SLIDING WINDOWS, yet it may also work with some vertical sliding (single hung) windows, depending upon the type of vinyl liners and balances used to construct the windows. Note: These locks will fit most all horizontal vinyl sliding windows and some vertical sliding windows, but not all of them. These locks feature an adjustable jaw that has a vise-like grip, and they are capable of opening up to 1/2 in. wide for a secure, non-marring hold on thick vinyl rails. When installing this lock, the cam style locking lever should be rotated hand-tight over the rail or vinyl edge to a sufficient torque prior to locking down the lever. Can be adjusted to fit on rail thicknesses ranging from 1/16 in. to 1/2 in. thick. Used as a secondary lock when window is shut and to secure the windows during ventilation. For a larger version of this lock (used on vinyl frame patio sliding doors) see Prime-Line part U 10547. No tools are required for installation.