door-dead-bolts The anti-theft chain can enhance security and provide intrusion protection, and cannot be unlocked outside, making you safer. It has an anti-off button to enhance the anti-theft ability.The chain is thickened and the lock is not easy to deform or break. Chain Gate Guard allows you to partially open the door to identify visitors or receive packages, and to provide reliable protection against intruders. A must have feature to protect yourself and your family., Manufacturer: sdSDGrw