4 pieces of child safety locks for windows and doors. This is a type of sliding door safety lock that prevents accidental opening of windows, providing extra security for your child and the window. It is recommended that the locks be installed at both the top and bottom for maximum security. Home security system has been improved. 8 Universal Keys. Comes with 8 universal keys, 4 pieces of sliding door locks, each sliding door lock comes with 2 keys, the keys are universal. Easy to Install. Easy to install the locks and convenient to use, comes with all safety fastening accessories, including stainless steel screw caps. Usage. Suitable for most hinged or sliding doors and windows. This design is very useful for homes, schools, and other places where children are present. International products have separate terms, are sold from abroad and may differ from local products, including International products have separate terms, are sold from abroad and may differ from local products, including fit, age recommendations, and product language, labeling or instructions. Including fit, age recommendations, and product language, labeling or instructions. This child safety device is used for most swinging or sliding doors and windows. Easy to install padlock and easy to use. Comes with all safety fastening accessories, prevents accidental opening of the window and protects interior safety. Universal locks perfect for most hinged or sliding doors and windows. Comes with all safety fastening accessories. Sold in a set of 4 patio sliding locks, with keys. Suggest that the blocks be installed at the top and bottom for maximum security. Each sliding lock comes with 2 keys, the keys are universal.