Fura Red, AM is a visible light—excitable fura-2 analog that offers unique possibilities for ratiometric measurement of Ca²⁺ in single cells by microphotometry, imaging or flow cytometry when used with single excitation, green-fluorescent calcium indicators. This acetoxymethyl (AM) ester form is useful for noninvasive intracellular loading and is also available in 1 mg amounts (F-3020).