The unique interlocking design of the BB70 box support bracket & BB70E bracket extender increases the rigidity of the system. The patent pending design adjusts to stud depths of 2.5 in to 6 in using these two parts, greatly reducing the complexity for stock locations and job site installation. The bracket is compatible with rapid ring pre-fab ring, adjustable plaster rings, the BBFS-18 floor stand and the BBCC cable containment clip.