U Bracket B is usually used as the structural support or connection point for shafts, timing pulley 18T, timing pulley 62T, timing pulley 90T and so on.  
                         
Features:
 ? With seven 8mm center holes that can be attached with 8mm shaft or bearings
 ? 44 x 4mm holes which are compatible with most Makeblock components     
 ? High-strength aluminum extrusion with anodized surface and 3mm of thickness designed for a long time service