Features: brand new and high quality High-quality materials: use aluminum alloy material, strong and durable. Punch-free installation: Each lock is equipped with a for key, slowly turning the for key through the hole, only need to use the for key to control, no additional installation tools. Controllable width: freely control the window width to prevent children or pets from crawling out of the window. Necessary items: Fix for windows to prevent children from falling and prevent thieves. Suitable for families, hotels, schools, kindergartens, etc. Specifications: Material: Aluminum Alloy Single Hole Wide Size: Approx. 2.3x2.3x2.9cm/0.91x0.91x1.14inch Single Hole Narrow Size: Approx. 2.3x1.8x2.9cm/0.91x0.71x1.14inch Double Hole Wide Size: Approx. 2.3x2.3x5.98cm/0.91x0.91x2.35inch Two-hole Narrow Size: Approx. 2.3x1.8x5.98cm/0.91x0.71x2.35inch Package Includes: 1x Window Safety Lock（with for Key） note: 1.Please allow 1-2cm errors due to manual measurement, make sure that you do not mind before you order. 2.Due to the difference between different monitors, the picture may not reflect the actual color of the item.