ArtRight T-Lock Security Locking Picture Hanger Set for Wood or Aluminum Frames, 10-Pack The standard "T-lock" system that has been used in hotels and institutions for years, using a proprietary T shaped screw Includes all pieces needed for security hanging of one wooden or aluminum frame Recommended for frames up to approximately 30" in width, weighing up to approximately 25 lbs. (heavier/wider frames require additional support brackets) Interlocking aluminum parts provide added strength and stability Rated to support up to 40 lbs. per lineal foot when properly installed