Attributes . The Stem Spindle is Made of High-Strength Quench-Hardened Stainless Steel Which Resists Strenuous Use; The Grand Gear Uses Stainless Steel that is Resistant to Wear and Deformation; Application of a Hard Coating on the Surface of the Crystal Makes the Gauge Highly Scratch-Resistant and Chemical-Resistant; Stem Dia. 8mm M2.5 x 0.45 Thread; Flat-Back; Shockproof Type . Names