MEASURE YOUR TRACK: The window lock is apply for sliding , sliding doors and vertical . please measure your window track size height mt be greater than 0.48inch (1.22cm) and width mt be less than 0.61inch (1.55cm) before ordering window locks. window locks is equipped with a vertical key, which can be applied to the middle track of the window.UPGRADE DESIGN: 2024 Upgrade design,our each window lock has two fixing holes,secure it on the window track,which greatly enhance the holding power of the lock,e double hole heavy /doors for added security. window locks are also equipped with pads to prevent scratches or damage to your window and improve stability.WIDE AGE: It ensures your family members safety,can control the window partially open or closed,effectively reduce the risk of children and falling from high ,by locking your , it can also protect your property against damage during heavy rains and . also, it prevent burglars and thieves. This sliding window lock for home,bedroom, kindergarten, office,etc.EASY TO INSTALL: No additional installation tools or drilling required,3-step quick installation. step1,place the lock to a suitable position. Step2,Insert gasket protect window track from scratches. Step3,tighten the screws,done! you can easily fix the window lock at any part with the vertical key or hex ,easy to ree and re-install.PACKAGE INCLUDES: 2 Sets of window locks for sliding . Great thanks for choosing and we care about the ctomer's purchase satisfaction.