Premium Material: 304 stainless steel latches and 202 stainless steel screws. Corrosion resistant, high toughness, rust protection. Durable enough to protect your baby and kids Easy to install: just need a screwdriver to complete the installation (comes with screws). A window opener can be completed in about 5 minutes. Please note that the gap between the window and the window frame should be 14-17mm Maximum opening: the window can be opened normally if the limiter is unlocked. Once fixed, the window can be opened to 65 degrees to the full extent. Effectively protects your child or pets from falling out of the window Wide Uses: These UPVC window opener locks are an ideal choice for home, kindergarten, school safety and more. Your safety is protected Contents: 1 left-handed blocker and 1 right-handed blocker in the package, with 8 screws required. 100% Money Back Guarantee. If you are unhappy with the purchase, please let us know. We will give you the best solution