Cal GreenTM 1 (potassium salt)

Cal Green 1 is a cell-impermeant fluorescent calcium indicator that is characterized by high quantum yield and low phototoxicity. Its peak excitation and emission wavelengths (506 and 531 nm, respectively) are comparable to standard fluorescein dyes, making Cal Green 1 appropriate for fluorescent microscopy. Cal Green 1 is ~5-fold brighter than fluo-3 at saturating calcium levels.