DIDS- and thiosulfate- sensitive anion exchanger mediating chloride, sulfate and oxalate transport (PubMed:11834742). Mediates chloride/bicarbonate exchange or chloride-independent bicarbonate extrusion thus assuring bicarbonate secretion (PubMed:15800055). 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 (By similarity). Inhibited by ammonium and thiosulfate. May form homodimers (in vitro). Predominantly expressed in lung at the luminal side of the bronchiolar and alveolar epithelium of lung. To a lower extent, also expressed in pancreas and prostate. Belongs to the SLC26A/SulP transporter (TC 2.A.53) family.