Easy to install: There is no need to install extra tools,it equips a hex key in each window locks,holding on the track by key control.<br/>Durable material: It is strong,solid and sturdy,exquisite workmanship,aluminum alloy frame and stainless steel screws that can be took full advantage of many times.<br/>Wide usage: It can be easily applied to most environments.By keeping the windows partially open and closed, the burglar-proof and thieves can prevent children from falling and protect the safety of their families while improving air circulation.<br/>Specifications:<br/>Size: 3 x 2.4 x 2.4 cm/ 1.18 x 0.94 x 0.94 inch(LWH)<br/>Material: aluminum alloy and stainless steel<br/>Quantity: 4 pieces<br/>Package includes:<br/>4 x Sliding window locks with keysDouble open design: compared to other window locks, this window locks adopt enhanced double open design, which obtain stronger friction force so that it can lock more solid for safer security material: made of aluminum alloy, which is sturdy and strong, and there's a yellow plastic cover outside the key handle, can serve you a long time Necessary items: open the screen window when the weather is hot in summer, which can improve air circulation, you can use the window locks to fix the screen window, it can prevent children from falling and prevent the thieves Wide Range of Applications: Suitable for sliding windows, vertical doors, sliding door tracks, sliding patio doors, sliding glass doors, etc. Suitable for fixed protection for homes, hotels, schools, yards, showers, storage rooms, garages, entertainment centers and more. Easy to Use: Our window locks security up and down window is easy to install. You only need to choose a suitable position to put the lock into the window slot, insert the key, adjust the distance between sliding window locks and fix the lock.