Binds voltage-independently to sodium channels (Nav) and shifts the voltage of activation toward more negative potentials (By similarity). This toxin is active against mammals and also affects neuromuscular preparations of frog. Expressed by the venom gland. Has the structural arrangement of an alpha-helix connected to antiparallel beta-sheets by disulfide bonds (CS-alpha/beta). Belongs to the long (4 C-C) scorpion toxin superfamily. Sodium channel inhibitor family. Beta subfamily.