The FS200-100 from AFL is a Optical Time Domain Reflectometer (OTDR) with Event Dead Zone 0.8 m, Attenuation Dead Zone 2.5 m, Optical Wavelength 1310 to 1550 nm, Dynamic Range 32 to 35 dB, Pulse Width 3 to 500 ns. More details for FS200-100 can be seen below.