... dual wavelengths, etc. C: Variable Optical Attenuator(VOA) This variable optical attenuator features continuously manually adjustable attenuation from zero to ... , c=3 for 3mm jacket pigtail, etc. D: Connector Type, d=FA for FC/APC, d=SU for SC ... UPC, d=N for no connectors, etc. Available Options: Connector Type: FC/APC, SC/APC, FC/PC, SC/PC, ... Ratio (dB) (PM only)> 20 Variable Optical Attenuator (VOA)