Deadbolts Welded twisted steel chain to match the door panel and chain bracket. This lock door protector is a safety lock device that allows the door to open slightly for safe viewing and ventilation Designed for hinged entry doors that swing inward to enter the residence our door chain can restrict the opening of the door, when the owner opens the door to confirm the identity of the visitor, the security chain lock can prevent sudden attacks or accidental break-ins outside the door, adding a layer of security., Manufacturer: CGJseFH