The 76908 Infrared Fiber Cable is made from Polycrystalline Fibers. Polycrystalline Fibers are extruded from pure AgCL:AgBr solid solution crystals. The core and cladding are the same material with a different ratio of AgCL and AgBr, to create the different index of refraction required to keep the light from leaking through the fiber. They can withstand CW CO2 laser power. This 1 meter, SMA terminated fiber cable has a AgCL:AgBr jacket. It has a 400 μm core diameter, a 500 μm cladding diameter, and numerical aperture of 0.25. PIR fibers transmit in the 4000 to 18000 nm range.