DIDS- and thiosulfate- sensitive anion exchanger mediating chloride, sulfate and oxalate transport (PubMed:15800055, PubMed:17120765). Mediates chloride/bicarbonate exchange or chloride-independent bicarbonate extrusion thus assuring bicarbonate secretion (PubMed:15800055, PubMed:17120765). May prefer chloride anions and mediate uncoupled chloride anion transport in an alternate-access mechanism where a saturable binding site is alternately exposed to either one or the other side of the membrane (PubMed:31339488). Inhibited by ammonium and thiosulfate. May form homodimers (in vitro). Expressed in stomach and trachea. Abundantly expressed in the apical domain of the surface epithelial cells and the deep cells in the gastric gland. Also expressed in heart, brain, lung and liver. Belongs to the SLC26A/SulP transporter (TC 2.A.53) family.