The Mahr Federal OMI-300P-10 Snap Gage for Outside diameters is used for rapid measurements of cylindrical components like shafts, bolts, pins, shanks as well as thickness and length measurements. This model has a measuring range of 9-10" / 226-251mm and includes Plain Anvils. The 300P Series Outside Diameter Snap Gages have a patented "Channel Lock" design that assures precisely parallel anvil surfaces throughout the full 25mm/1" range of adjustment. All gages in this series are fully adjustable with positive position locking at any point within the range. They feature large, 15.5mm/.61" square tungsten carbide anvils that provide flat, parallel, long-lasting working surfaces and ensuring precision that lasts. INDICATOR SOLD SEPARATELY.