The material is made of high-quality materials that can withstand higher pressure and are not easily damaged. Excellent safety and high-quality choke cables can improve safety, home health and safety, as well as infant/child safety. Easy to install made of 19cm long steel wire, with self tapping screws and wrench, just install a screwdriver or drill bit. Very suitable 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. Lock and unlock special restriction design, providing 19cm restriction and 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 distance that the window can open is limited. With the key, you can unplug the cable from one end and fully open the window. The appearance is novel, the lines are smooth, and it can be bent freely. The cable distance can reach 18.5cm. The unique lock cylinder greatly improves the safety of the door lock. Package includes: 4 pieces