This Texas Security Bolt Lock is constructed of stamped steel and comes in a beautiful, corrosion-resistant, painted finish. It is a maximum security locking device that is designed for use with inswing doors. This locking hardware installs into jamb jack stud with 3-1/2 inch long screws, to ensure the strongest hold. When the ring is engaged into the lock plate, it is designed to block the in-swinging door from opening, and it meets Texas apartment codes. For best results, follow the installation instructions included with each package.