Expressed by the venom duct. The cysteine framework is VIII (C-C-C-C-C-C-C-C-C-C). Contains 5 disulfide bonds. The gene superfamily associated with this precursor was described as 'B superfamily' in PubMed:23152539, but this name was already assigned to the conantokin precursors, therefore the superfamily was renamed 'B2 superfamily'. Belongs to the conotoxin B2 family.