Upgraded Double Glazed Locks - Double glazed locks can be applied to heavy doors or windows for added security. And it will be more strong, solid and sturdy, exquisite workmanship, aluminum alloy frame and stainless steel screws which can be reused many times Quantity and size - sliding double window locks with 4 keys; approximate volume 6 x 2.54 x 2.4 cm / 2.36 x 0.95 x 0.95 inch (LWH), apply to track heights greater than 1.2 cm / 0.47 inch, track thickness track not greater than 1.6 cm / 0.63 inch (does not apply to the middle track) window, please check your window track before purchasing) Easy to install - there is no need to install additional tools, it has a hex key in each window lock, held by a key control on the track. Designed for horizontal/vertical windows and sliding glass doors; Not for plastic window frames Wide use - can be easily applied to most environments; By keeping windows partially open and closed, burglars and thieves can prevent children from falling and protect the safety of their families while improving air circulation Easy to install: There is no need to install additional tools, it has a hex key in each window lock, kept on track by key control. Durable material: It is strong, sturdy and sturdy, with exquisite workmanship, aluminum alloy frame and stainless steel screws that can be fully exploited. Wide use: It can be easily applied to most environments. By keeping windows partially open and burglar-proof, anti-theft and thieves can prevent children from falling and protect the safety of their families while improving air circulation. Features: Size: 6 x 2.4 x 2.4 cm / 2.36 x 0.94 x 0.94 inch (LWH) Material: aluminum alloy and stainless steel Package includes: 4 x double sliding window locks with 4 keys Note: Multiple locks can be applied to heavy doors to enhance security. getveryrich