Material Made of high quality material, can withstand higher pressure, not easy to damage. Excellent safety High quality choke cable for increased safety, health and safety at home and baby/child safety. Easy to install Made of steel wire measuring 19cm long, comes with self-tapping screws and wrenches, just a screwdriver or drill to install. Widely used Ideal for PVC, aluminum, wood, composite doors and windows. Use on double-hung, casement and sliding windows; balcony doors, guest room doors, etc. Locked and unlocked Special limiting design provides 19cm restriction and fresh air, and the window can be fully opened when the cable is pulled out at one end using the wrench. Once the cable is in place, the distance the window can be opened is limited. Using the wrench, you can remove the cable from one end and open the window fully. New shape, smooth line, can be bent at will, cable distance up to 18.5 cm. Unique lock core, greatly increased the security of the door lock. Package included: 4 pcs