Enables small conductance calcium-activated potassium channel activity. Involved in membrane repolarization during atrial cardiac muscle cell action potential and potassium ion transmembrane transport. Acts upstream of or within ion transport. Located in several cellular components, including T-tubule; Z disc; and smooth endoplasmic reticulum. Is expressed in brain; heart; and heart ventricle. Used to study Parkinson's disease. Orthologous to human KCNN2 (potassium calcium-activated channel subfamily N member 2). [provided by Alliance of Genome Resources, Apr 2022]