Lapmaster Monochromatic Lights are used to measure surface flatness within millionths of an inch. These self-contained units use a helium light tube to produce a glare free light of known wavelength (23.2 millionths of an inch).

When used with Lapmaster Optical Flats, contrasting light and dark bands are readily observed on most reflective or semi-reflective surfaces. Surface flatness to within .000001" is quickly and easily measured on parts ranging in size up to 10.5" in diameter.