Fowler 52-229-204-0 Series Swiss Style Outside Inch Micrometer, 2-3" Measuring Range, +/- 0.0002" Accuracy, 0.0001" Graduation 0.0001" reading Carbide measuring faces Insulated frame Ratchet thimble and locking lever Microfine graduations Sizes over 1" include standar Range :3 - 4" Accuracy : ± 0.0002""Unique friction design allows one hand operation Swiss style design, balance and quality Friction/Ratchet thimble assures you of consistent readings at all times. Barrel, thimble and frame are satin chrome finished; microfine graduations allow easy reading Measuring faces are carbide tipped A wrench is included, permitting quick and easy zero adjustment on sleeve Flatness: .00003". Parallelism: .00005" for the 01"/025mm measuring range Fully insulated frame isolates heat from the operator's hand One piece design, extremely well balanced, lightweight (01"/25mm size weighs only 7-34 oz.) Positive lever-locking clamp ensures reliable measurement at all times Spindle diameter .256"/6.5mm. Anvil and spindle hardened and precision ground Meets or exceeds Fed. specs for accuracy Standard included Includes a case