Apply to windows and doors: make sure the track heights more than 1.5 cm/ 0.6 inches, track thickness no more than 1.6 cm/ 0.63 inches, not applicable to the middle track of the window, please check your window track before buying<br>Double open design: compared to other window locks, this window locks adopt enhanced double open design, which obtain stronger friction force so that it can lock more solid for safer security<br>Quality material: made of aluminum alloy, which is sturdy and strong, and there's a yellow plastic cover outside the key handle, can serve you a long time<br>Necessary items: open the screen window when the weather is hot in summer, which can improve air circulation, you can use the window locks to fix the screen window, it can prevent children from falling and prevent the thieves<br>What you get: 4 x sliding window locks with key; Note: multiple locks can be applied to heavy window or door together to increase safety