Hobbes 257835PK1 SMARTFiber Pro and OPTISource 850nm/1300nm Kit includes a SMARTFiber Pro power meter and an OPTISource 850nm/1300nm fiber optic light source for high accuracy optical power measurements. Hobbes 257835PK1 can be used in fiber loss measurement, fiber attenuation measurement, and fiber cable identification by using modulated light source.