Anion-selective channel with Ca(2+)-dependent and voltage- independent gating. Permeable to small monovalent anions with selectivity for bromide > chloride > nitrate > fluoride (By similarity). Operates in the endoplasmic reticulum (ER) membrane where it mediates chloride efflux to compensate for the loss of positive charges from the ER lumen upon Ca(2+) release. Contributes to the maintenance of ER Ca(2+) pools and activation of unfolded protein response to prevent accumulation of misfolded proteins in the ER lumen. Particularly involved in ER homeostasis mechanisms underlying motor neurons and retinal photoreceptors survival (By similarity) (PubMed:25698737, PubMed:30157172, PubMed:37142673). {ECO:0000250|UniProtKB:Q99LI2, ECO:0000269|PubMed:25698737, ECO:0000269|PubMed:30157172, ECO:0000269|PubMed:37142673}. This is the function of CLCC1 (chloride channel CLIC like 1, Ensembl gene identifier ENSG00000121940).