The MMC850-50 from Idealphotonics Inc is a Fiber Optic Coupler with Wavelength 850 nm, Directivity 40 dB, Insertion Loss 1.3, 1.8, 2.4, 3.1, 3.9, 4.9, 6.2, 8, 11.3 dB, Operating Temperature -5 to 70 Degree C. More details for MMC850-50 can be seen below.