Narrow Lock Frame Design：Keeps the chain in place when the doorstop isn't in use, door and frame damage from a hanging chain. Designed for hinged entry doors that swing inward to enter the residence Ideal for front doors, apartment doors, hotel rooms, and even sliding glass patio doors, additional security for your home or office doors are within reach! All installation hardwares are included in the package,so you can mount it easily. Easy installation with just a few simple tools Door chain lock allows you to identify visitors before fully opening the door, providing additional security and preventing intruders from easily entering your property.