Expressed by the venom duct. The presence of a 'disulfide through disulfide knot' structurally defines this protein as a knottin. The cysteine framework is VI/VII (C-C-CC-C-C). This peptide corresponds to allele E1i. Has not been merged with other alleles since they may differ due to geographic variation (see strain in PubMed:19606224). Belongs to the conotoxin O1 superfamily.