Similar to the BB, however, has the additional feature of a grade 12.9 socket screw at the back to allow adjustment to suit the flange thickness without the need for packings. Normally used when it is difficult to determine the actual thickness of the steelwork flange. Suitable for parallel flanges and tapered flanges up to 5 degrees. Manufactured from ductile iron. Hot dip galvanised as standard. 5 to 1 factor of safety. Lloyds register approved.