Series No. 52-248 offers Fowler standards of fine quality and accuracy. A variety of sizes covers a range of measuring applications. Hammertone blue baked enamel finish Microfine graduations on satin chrome finish and carbide tipped measuring faces Friction stop thimble for exact and repetitive readings Flatness: .00076mm Parallelism: .000125mm for 0-25mm Spindle thread is hardened, ground and lapped Anvil & spindle hardened and precision ground with microlap finish on tips All micrometers meet or exceed U.S. Federal specifications for accuracy Includes a wrench and case