The mounting bracket kit is used to attach 50mm plastic duct to central office or exchange steel work. i.e. It allows 50mm ducting to be installed with the bracket assemblies and (12mm) suspension rod provided. The kit consists of 50mm duct mounting bracket, 6mm nut & washer, straight bracket, 150mm long threaded rod with nuts & washers to suit. The mounting bracket grips the 50mm ducting and bolts to the straight bracket, using the nut & washer provided. The straight bracket bolts to the (12mm) threaded steel rod, which attaches to the building steel work.