JW3109Handheld Light Source is designed for optimal use withJW3208Optical Power Meter for measuring optical loss on both single mode and multimode fiber cable. 5V batteries,User Manual, Cotton. VIAVI offers the most comprehensive light source and power meter kits for fiber optic networks. Multiple wavelength combinations are available for field, lab, and manufacturing environments. VIAVI light sources offer versatility in measuring fiber optic light continuity, loss and quality in field. Discover EXFO's broad range of optical light sources that cater to various testing requirements: singlemode or multimode, polarized or non-polarized, broadband or narrowband, tunable, ITU-wavelength-centered and much more.