Potassium channel inhibitor that is the most potent on Kv1.1/KCNA1 (IC(50)=671.95 nM), Kv1.2/KCNA2 (IC(50)=167.36 nM), and Kv1.6/KCNA6 (IC(50)=115.68 nM), and less potent on Kv1.3/KCNA3 (20% inhibition at 3 uM) and on shaker IR (15% inhibition at 3 uM). It inhibits potassium currents, not only by blocking the potassium current of Kv1.2/KCNA2, but by altering the energetics of activation of Kv1.1/KCNA1 and Kv1.6/KCNA6. Has the structural arrangement of two alpha-helices stabilized by disulfide bonds (CSalpha/alpha 2(S-S)). Does not show effect on rNav1.2/SCN2A, rNav1.4/SCN4A and B.germanica Nav1 (BgNav1), rKv1.4/KCNA4, rKv1.5/KCNA4, rKv2.1/KCNB1, hKv3.1/KCNC1, rKv4.2/KCND2, rKv4.3/KCND2, and hKv11.1/ERG1/HERG (3 uM toxin tested). Belongs to the sea anemone type 6 potassium channel toxin family.