CHILDREN'S SAFETY: We all know that children are active and parents are unavoidable to worry about their children's safety. Our windows and sliding door safety locks can firmly fix doors and windows to prevent children from falling from open windows while playing.GUARD AGAINST THEFT: If the window lock is not strong enough, thieves may take the opportunity to enter. Screw-fixed window locks are stronger than ordinary paste-fixed window locks.PREMIUM MATERIAL: Made of high-quality aluminum alloy, it is durable and beautiful, simple and elegant.EASY TO INSTALL: WIth Installation screw and reinforcement gasket in the package, just tightening the screw to complete the Installation.MULTI-PACK: 4 PCS to install multiple doors and windows at home which is economical and practical.