Crafted from high-quality materials, these restrictors are built to withstand high pressure and resist damage. Enhanced safety features and premium-quality restrictor cables improve home security, health, and child safety. Easy to install with 19cm steel wire, self-tapping screws, and a wrench simply use a screwdriver or drill. Perfect for large PVC, aluminum, wood, and composite doors and windows. Suitable for double-hung windows, casement windows, and sliding windows; balcony doors, guest room doors, etc. The special locking design provides a 19cm restriction for fresh air, and the window can be fully opened by removing one end of the cable with a key. When the cable is in place, the window's opening distance is limited. The key allows you to detach the cable from one end and fully open the window. The sleek, modern design features smooth lines and flexible bending. The cable distance reaches 18.5cm. The unique lock cylinder significantly enhances door lock security. Package includes: 4 pieces