4 Pcs Door Window Locks This is a patio sliding door safety lock, which prevents accidental opening of windows, providing added safety for your child and your windows. Suggests mounting the locks at the top and bottom for maximum security, home security system upgrade. 8 Universal Keys Come with 8 universal keys, there are 4 sliding locks. Each sliding lock comes with 2 keys, the keys are universal. Zinc Alloy Copper Zinc alloy, anti-rust, durable and quality. Easy to install Easy to install and use padlocks, equipped with all safety accessories, including stainless steel screw caps. Application Suitable for most swing or sliding doors and gates, this design is very useful for homes, schools and other places for children.