Series - bpb bpbt made from solid brass to provide reliable accuracy and corrosion resistance polished finish supplied with a strong spool of nylon cord that can be wound around the top of the bob series bpbt is provided with a hardened & ground removable tip for greater accuracy and longer life model size (mm) net weight (kgs.) bpb-1 bpbt-1 ø 12 x 50 0.06 bpb-2 bpbt-2 ø 12 x 75 0.09 bpb-3 bpbt-3 ø 12 x 100 0.12 bpb-4 bpbt-4 ø 12 x