Background potassium channel. Rectification is dependent on external potassium concentration. Acts as an outwardly rectifying channel but as external potassium levels increase, this is reversed. Widespread expression in adult, strongest expression in muscle, brain and ovary. Also present at low levels in larva and embryo. Inhibited by barium. Belongs to the two pore domain potassium channel (TC 1.A.1.8) family.