4" round swivel fixture hangers with 1/2 or 3/4" pipe and hinged doors for round/octagon boxes and rings are used to hang industrial lighting fixtures, security cameras, motion detectors, occupancy sensors and other electrical/electronic devices from overhead ceiling installations. They are great in industrial settings where the pipe stem or fixture might be subjected to motion or vibration. Their hinged door design allows the installer to mount the cover on box and hang fixtures in one easy step and wire termination can be completed with the door open. They have a “hands free” labor saving installation; fixture hanging is now a one man job!