Potassium channel blocker. At 3 uM, this toxin blocks voltage-independently voltage-gated potassium channels rKv1.2/KCNA2 (25%), hKv1.3/KCNA3 (27%), rKv4.2/KCND2 (25%), Kv10.1/KCNH1/EAG1 (15%), Kv11/hERG (12%), and Shaker-IR (10%). On hKv1.3/KCNA3, the IC(50) is 17.1 +-3.3 uM. Expressed by the venom gland. The presence of a 'disulfide through disulfide knot' structurally defines this protein as a knottin. Is completely devoid of the classical secondary structure elements (alpha-helix and/or beta-strand). Does not block all sodium channels tested and several potassium channels. Does not block the following voltage-gated potassium channels: rKv1.1/KCNA1, rKv1.1/KCNA1, rKv1.5/KCNA5, rKv1.6/KCNA6, rKv2.1/KCNB1, hKv3.1/KCNC1, and Kv7.2/KCNQ2. Does not block the following voltage-gated sodium channels: rNav1.1/SCN1A, rNav1.4/SCN4A, hNav1.5/SCN5A, mNav1.6/SCN8A, and DmNav1/para. Belongs to the short scorpion toxin superfamily. Potassium channel inhibitor family. Epsilon-KTx 01 subfamily. Truncated N-terminus.