Improved Double Glazed Locks - Double glazed locks can be applied on heavy doors or windows for added security. And it will be more solid, solid and sturdy, exquisite workmanship, aluminum alloy frame and stainless steel screws that can be reused several 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, thickness of the non-superior way to 1.6cm / 0.63 inch (not applicable to middle lane) window, please check your window track before purchasing) Easy to install - no need to install additional tools, it has a hex key in each window lock, held by a keyed 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, anti-theft devices and thieves can prevent children from falling and protect