Reversibly blocks the high conductance calcium-activated potassium channels composed of only alpha subunits (KCa1.1/KCNMA1). Unreversibly blocks the high conductance calcium-activated potassium channels composed of alpha and beta1 subunits (KCNMA1 and KCNMB1). Unreversibly and weakly blocks the high conductance calcium-activated potassium channels composed of alpha and beta4 (KCNMA1 and KCNMB4). Expressed by the venom gland. Has the structural arrangement of an alpha-helix connected to antiparallel beta-sheets by disulfide bonds (CS-alpha/beta). Does not inhibit other potassium channels such as dSlo, Kv1.1/KCNA1, Kv11.1/KCNH2/ERG1, Kir2.2/KCNJ12, Shaker-IR, and voltage-independent/calcium-activated SK1/KCNN1, SK2/KCNN2 and SK3/KCNN3. Belongs to the short scorpion toxin superfamily. Potassium channel inhibitor family. Alpha-KTx 01 subfamily.