With ratchet stop, lock nut. Includes case. The depths of holes, slots, shoulders, and projections can be measured to 0.01mm with these fine tools. The No. 440 gages are furnished with a 63mm base and 3.2mm diameter measuring rods. A base shape design that will automatically position the fingers so that the base is easily held in place for measuring stability. All precision screws are ground and lapped. All bases and rods are hardened ground and lapped for permanent accuracy. All reading surfaces have a satin chrome finish that resists rust and provides a non-glare background for the sharp lines and figures. All measuring rods are adjustable. The combination of ratchet and speeder for uniform pressure and quicker adjustment. Ring-type lock nut for quick and sure locking.