The Mitutoyo 2904SB Standard Type Series 2 Dial Indicator has an outer frame with an outside diameter of 57mm. All types come with limit pins and an outer frame clamp as standard. Secured adhesion between the outer frame and crystal as well as the use of an O-ring ensure countermeasures against water and oil permeation via the front face. The stem spindle is made of high-strength quench-hardened stainless steel which resists strenuous use and a carbide contact point is used. The grand gear uses stainless steel that is resistant to wear and deformation an application of hard coating on the surface of the crystal makes the gauge highly scratch as well as chemical resistant. This model is a Reverse Reading Type and has a Flat Back with a range of 1" and .1" per revolution, .001" graduation and 100-0 Dial Reading with a 3/8" Stem.