The JDS Uniphase Fitel 5500L Manual Variable Optical Attenuators (VOA) is a test and development instrument in laboratory applications. They provide continuously variable attenuation range of up to 60 dB with calibration wavelengths of 1300 nm or 1550 nm. Attenuation is set manually with large mitutoyo 0 - 2 (0.0002 resolution) inch micrometer. There is digital readout in dB. Unlike programmable attenuators, the attenuation level is maintained when the micrometer sets. The attenuators use JDS Uniphase'Fitel new technology to produce accurate attenuation settings with low insertion loss and excellent return loss. Key Features Operation Wavelength 1310 or 1550nm Resolution 0.1dB or better Dynamic range 0-60dB. Low insertion Loss and Return Loss Compact size and Light Weight