For facs or microscopy Alexa 1 conjugate.Alexa Fluor 488 has the same range to that of fluorescein isothiocyanate (FITC), yet the Anti-alpha MSH has a very high photo stability. As a result of this photo stability, it has turned into an antibody for fluorescent microscopy and FACS FLOW cytometry. It is distinguished in the FL1 of a FACS-Calibur or FACScan. Also Alexa Fluor 488 is pH stable.If you buy Antibodies supplied by Bioss Primary Conjugated Antibodies. ALEXA FLUOR they should be stored frozen at - 24°C for long term storage and for short term at + 5°C.