Shifts the voltage of activation of para/tipE voltage-dependent sodium channels (Nav) toward more negative potentials. Expressed by the venom gland. Has the structural arrangement of an alpha-helix connected to antiparallel beta-sheets by disulfide bonds (CS-alpha/beta). Is totally devoid of toxicity when intracerebroventricularly injected into mice and does not compete with radiolabeled voltage-gated potassium and sodium channel toxins in binding experiments on rat brain synaptosomes. Belongs to the long (3 C-C) scorpion toxin superfamily. Sodium channel inhibitor family. Beta subfamily.