Safety locks: The window locks can be adjusted freely with a screw wrench, and the window remains partially open or closed to prevent children and cats from opening the window, prevent thieves from entering and ensure the safety of the balcony Easy to install: The window lock does not need to be drilled, and requires no installation tools. Very easy to install, a turn of the key is enough to place the lock. And put a plastic protection between the screw and the guide rail to avoid leaving marks Material: the window lock is made of high quality metal, exquisite workmanship, sturdy and durable, strong rust and corrosion, and can be reused Quantity: There are 4 window locks, size 30 x 25 x 24mm, suitable for sliding doors and windows with guide rail thickness no more than 16mm Use: Sliding window locks can be used for aluminum alloy windows, patio doors, horizontal/vertical sliding windows and sliding doors to protect the safety of families and children