K(+) channel that conducts voltage-dependent outward rectifying currents upon membrane depolarization. Voltage sensing is coupled to K(+) electrochemical gradient in an 'ion flux gating' mode where outward but not inward ion flow opens the gate (PubMed:11263999, PubMed:12724142, PubMed:14985088, PubMed:26919430, PubMed:28928238, PubMed:34032641, PubMed:36063992). Homo- and heterodimerizes to form functional channels with distinct regulatory and gating properties (PubMed:36063992). In pancreatic islets, conducts K(+) countercurrents for Ca(2+) release from the endoplasmic reticulum (ER) and regulates the frequency and duration of cytosolic Ca(2+) oscillations coupled to secretion of pancreatic hormones (PubMed:26239056, PubMed:28928238, PubMed:29402588, PubMed:34032641). In pancreatic beta cells, drives ER Ca(2+) efflux, which in turn activates Ca(2+)-dependent plasma membrane K(+) slow currents and cytosolic Ca(2+) influx, overall contributing to synchronous cytosolic Ca(2+) oscillations. Limits glucose-induced cytosolic Ca(2+) oscillations coupled to second-phase INS secretion (PubMed:26239056, PubMed:28928238, PubMed:34032641). Contributes to beta cell adaptation to acute inflammation by maintaining normal cytosolic Ca(2+) levels and INS secretion (By similarity). May regulate beta cell mitochondrial Ca(2+) levels either indirectly via ER Ca(2+) efflux or directly by hyperpolarizing the mitochondrial membrane potential. Limits mitochondrial Ca(2+) oscillations and ATP production involved in glucose homeostasis upon metabolic stress (By similarity). In pancreatic delta cells, limits Ca(2+)-induced Ca(2+)-release involved in somatostatin secretion and modulates islet paracrine signaling involved in glucagon secretion (PubMed:29402588). Permeable to other monovalent cations such as Rb(+) and Cs(+) (By similarity) (PubMed:26919430). {ECO:0000250|UniProtKB:G5E845, ECO:0000250|UniProtKB:Q96T54, ECO:0000269|PubMed:11263999, ECO:0000269|PubMed:12724142, ECO:0000269|PubMed:14985088, ECO:0000269|PubMed:26239056, ECO:0000269|PubMed:26919430, ECO:0000269|PubMed:28928238, ECO:0000269|PubMed:29402588, ECO:0000269|PubMed:34032641, ECO:0000269|PubMed:36063992}. This is the function of KCNK16 (potassium two pore domain channel subfamily K member 16, ENSG00000095981).