The CrackScope is a small size, lightweight and conveniently portable microscope with a 25× magnification. It has a build-in scale for crack-width measurement and another scale on the focusing adjustment ring for depth indication.
The magnification of the CrackScope is 25 times. The built-in 3-mm scale has a least division of 0.05 mm, allowing the width of cracks to be estimated within ±0.025 mm. Depth measurement is achieved by focusing at the bottom of a depression and then focusing at the perimeter of the depression. By reading the scale engraved on the focusing ring and the needle of the lens barrel, depths can be measured with an accuracy of ±0.05 mm.