Dimensions: volume about 3 x 2.4 x 2.4 cm/ 1.18 x 0.94 x 0.94 inch (LWH), suitable for track height greater than 1.5 cm/ 0.6 inch, track thickness not greater than 1.6 cm/ 0.63 inch (not suitable for window middle track, buy Please check your window track before) Easy installation: No need to install additional tools, each window lock is equipped with a hex key, which is fixed to the track by key control DURABLE MATERIALS: Strong, sturdy, fine workmanship, aluminum alloy frame and stainless steel screws can be reused many times Versatile: Can be easily applied to most environments; by keeping windows partially open and closed, burglars and thieves can prevent children from falling and keep your family safe while improving air circulation Quantity: 13 Sliding Window Locks with Key; Note: Heavy doors or windows can use multiple locks for added security