DIDS- and thiosulfate- sensitive anion exchanger mediating chloride, sulfate and oxalate transport. Mediates chloride/bicarbonate exchange or chloride-independent bicarbonate extrusion thus assuring bicarbonate secretion. 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. Inhibited by ammonium and thiosulfate. May form homodimers (in vitro). Belongs to the SLC26A/SulP transporter (TC 2.A.53) family.