Performs easy and accurate measurement of narrow or recessed areas, plus inside and outside diameters that dial indicators cannot access. Resistant to water and dust thanks to the one-piece bezel and crystal design with O-ring. The glare-free flat crystal face has a scratch-resistant coating. 0-4-0 Scale, 3/8" Stem, Stylus .079" Contact Point, 15mm Length, Anti-Magnet, Jeweled Bearing.