Dry film thickness gauges are used to inspect finished coatings. Mechanical coating thickness gauges provide several advantages. They are very handy, easy to transport, and easy to use (even by assistants). Robust construction, direct reading of measurements. Measurements can be made on any surface, whether glass, wood, metal or plastic, since it uses a purely mechanical measuring principle. Mechanical coating thickness gauges are very inexpensive compared to other systems. Wet-film thickness gauges are used to inspect freshly applied layers, they enable the calculation of the remaining dry film thickness. If deviations from the target value are detected, these can be corrected immediately.