Inhibits voltage-gated sodium channels without significantly altering the voltage dependence of activation or inactivation. The toxin preferentially inhibits hNav1.7/SCN9A (IC(50)=2.1 nM) > hNav1.6/SCN8A > hNav1.2/SCN2A > hNav1.1/SCN1A > hNav1.3/SCN3A channels in fluorescent assays. The toxin exhibits analgesic properties by reversing spontaneous pain induced in mice by intraplantar injection with OD1 (AC P84646), a scorpion toxin that potentiates hNav1.7/SCN9A. Expressed by the venom gland. The presence of a 'disulfide through disulfide knot' structurally defines this protein as a knottin. Monoisotopic mass. Does not affect human voltage-gated calcium channels (Cav) or nicotinic acetylcholine receptors (nAChR) at 5 uM. Belongs to the neurotoxin 10 (Hwtx-1) family. 55 (ProTx-III) subfamily.