Enhanced Window Security: These letter box lock feature a screw reinforced design that integrates the base and locking arm for maximum durability. The door jammer prevents unauthorized entry while allowing controlled ventilation for child and pet safety. Premium Material: Made from high quality plastic, the window latch boasts a wear resistant white finish that resists rust. The sash window stopper maintains structural integrity through long term use on various window types. Simple Installation: The sash window locks set included uPVC screws and packers, the door jammers for inside doors easily installs on reinforced windows. Online instructions guide the window lock installation process for perfect alignment on different profiles. Compatibility: Ideal for PVC, wood and composite frames, the window safety locks works on vertical sliding and double hung windows. The window sash jammer locks provides universal protection for homes, apartments and offices. Dual Pack: Each order contains two window anti theft locks with all necessary hardware. The sash locks for internal doors set makes an practical gift that enhances home security for family and friends., Manufacturer: Koprek