Insecticidal toxin that potently and irreversibly blocks voltage-gated sodium channels (Nav) in cockroach dorsal unpaired median (DUM) neurons (IC(50)=833.7 nM) (PubMed:29880771). It does not change both the steady-state activation and inactivation curves, suggesting it acts as a pore blocker (possibly at Nav site 1) (PubMed:29880771). Does not show toxicity when intraperitoneally injected into mouse (PubMed:29880771). Expressed by the venom gland. The presence of a 'disulfide through disulfide knot' structurally defines this protein as a knottin. LD(50) is 2.8 nmol/g of body weight, when intraperitoneally injected into cockroaches. Hardly affects the DUM voltage-gated potassium channels (Kv) (15.4% inhibition at 10 uM) and the DUM high-voltage-activated calcium channels (HVA Cav) (PubMed:29880771). Does not affect or only very weakly voltage-gated sodium channels Nav1.3/SNC3A (<10% at 15 uM), Nav1.4//SNC4A (<10% at 15 uM), Nav1.5/SNC5A (no inhibition at 15 uM), Nav1.7/SNC9A (no inhibition at 15 uM), and Nav1.8/SNC10A (no inhibition at 15 uM), HVA Cav, and Kv in rat dorsal root ganglion (DRG) neurons (PubMed:29880771). Belongs to the neurotoxin 10 (Hwtx-1) family.