Membrane-impermeant calcium indictor that can be loaded into cells via microinjection or scrape loading.    Kd: 1 uM  &lamba;Ex/&lamba; Em (low or high [Ca2 ])= 556nm/576nm  ε (556 nm) = 80,000 M-1cm-1.  Orange red solid soluble in DMSO and water (pH >6)  Store at 4°C and protect from light, especially in solution  C40H39K3N4O11  MW: 869