Improved Double Glazed Locks - Double glazed locks can be applied to 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 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, thickness of the lane not larger than 1.6cm / 0.63 inch (does not apply to the middle lane) window, please check your window track before purchasing) Easy to install - it is not necessary 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, anti-theft devices and thieves can prevent children from falling and protect the safety of their families while improving air circulation Quantity: 4 pieces Note: this does not include other things, the color is based on the first picture, and other pictures only show the effect Due to the differences between different monitors, the picture may not reflect the actual color of the item. Due to manual measurement. Please allow deviation. Thank you