Progressive Heavy Duty High Quality Solid Brass Security Chain Door Guard This heavy duty door chain guard is unlike all the others, it is way stronger and heavier and is the only one that has a riveted steel roller chain. Provides security, resisting forced entry, while alowing door to be open 3 inches. Mounting and fastening hardware includes only screws for wood doors and wood frames. We manufacture and provide self drilling screws for steel doors and steel frames.