Spider venom neurotoxin that blocks voltage-gated sodium channels Nav1.3/SCN3A and Nav1.8/SCN10A in human (IC(50)=2 uM and IC(50)=4 uM, respectively) and rat (IC(50)=2 uM and IC(50)=2.5 uM, respectively). Expressed by the venom gland. The presence of a 'disulfide through disulfide knot' structurally defines this protein as a knottin. Has no effect on voltage-gated potassium channel human Kv11.1/KCNH2/ERG at 17 uM (Ref.1). Belongs to the neurotoxin 10 (Hwtx-1) family. 34 (Jztx-26) subfamily.