Safety locks: The window locks can be freely adjusted with a screw key, and the window remains partially open or closed to prevent children and cats from opening the window, prevent thieves to enter and provide security. Easy to install: no need. to drill the window lock and no installation tools required. Very easy to install, just a turn of the key 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, fine workmanship, strong and durable, rust and corrosion resistant, 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 Usage: 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