【4pcs Door and Window Locks】This is a patio sliding door safety lock, which prevents windows from being opened accidentally, extra security for your child and your window. Suggest that the blocks are mounted high and low for maximum security, updated home security system. 【8 Universal Keys】Comes with 8 universal keys, there are 4 sliding locks. Each sliding lock comes with 2 keys, the keys are universal. 【Zinc Alloy】Zinc alloy copper, anti-rust protection, durable and quality. 【Easy to Install】Easy to install, easy to use padlocks, come with all security accessories, including stainless steel screw caps. 【Application】Suitable for most swinging or sliding doors and gates, this design is very useful for homes, schools and other places for children.