Measurement Purpose Monochromatic Lights are used to measure surface flatness within millionths of an inch. These Monochromatic Lights are self-contained units. These Monochromatic Lights are used a helium light tube to produce a glare free light of known wavelength [23.2 millionths of an inch]. These Measurement Purpose Monochromatic Lights can measure surface flatness to within .000001" on parts ranging in size up to 10.5" in diameter.
