Reduces potassium currents through Kv1.2/KCNA2 and Kv1.3/KCNA3 voltage-gated potassium channels. Expressed by the venom gland. Has the structural arrangement of an alpha-helix connected to antiparallel beta-sheets by disulfide bonds (CS-alpha/beta). Has no effect on Kv1.1/KCNA1, Kv1.4/KCNA4, Kv1.5/KCNA5, shaker IR or Kv11.1/KCNH2 channels. Belongs to the short scorpion toxin superfamily. Potassium channel inhibitor family. Alpha-KTx 20 subfamily.