Improved Double Glass Lock - Double glass locks can be used on heavy duty doors or windows for added security. And more sturdy, durable and exquisite workmanship, aluminum alloy frame and stainless steel screws, can be reused for many times EASY TO INSTALL - No additional tools are required for installation. installation, each window lock has a hex key secured by a control key on the track. Designed for horizontal/vertical windows and sliding glass doors; not suitable for plastic window frames Versatile - can be easily applied to most environments; by keeping windows partially open and closed, locks and thieves can prevent children from falling and protect your family while improving air circulation Size: 6*3*2.4cm Packing List: 4* door and window anti-theft lock We only sell door and window anti-theft locks, not other items in the picture. Individual products and pictures may vary slightly due to factors such as manual measurement and monitor differences.