Rhod-2 AM is an acetoxymethyl (AM) ester of the red fluorescent calcium indicator rhod-2. The AM group facilitates cellular uptake and is removed by cytoplasmic esterases, resulting in intracellular accumulation of rhod-2. Rhod-2 AM selectively accumulates within mitochondria and, as a result, is commonly used to monitor calcium changes within this organelle. Excitation and emission maxima are 557 and 581 nm, respectively.