Optical attenuator Yin type is adapter standard high-precision flange and refined, used for all kinds of optical fiber transmission lines, the attenuation performance is stable and reliable, and the precision of characteristics and wavelength can realize adapter and not the dual function, attenuators, high additional loss attenuation precision optical fiber distribution frames used low speed network system, optical fiber transmission system, fixed type can be divided by attenuator, Yin and Yang, flange and can be divided into SC, according to the model, ST, FC LC, etc.