Features: quality alloy measuring heads can be used for various internal size measurement, fine workmanship and no burr. Clear marking line for convenient reading. main micrometer is made of stainless steel with plated , wearresisting- and . Designed with locking device, machinery structure it more intuitive and convenient to read. Builtin- ratchet stop device accurate repetitive readings. Specifications: Type: Inside micrometer Measuring Range: 5mm30mm~ Material: Stainless steel : 001mm. Weight: 268gapprox(.) : of measuring anvil heads with a soft cloth, then rotate measuring device to two measuring . If two lines of differential sleeve and fixed do not alignment, use following two methods to adjust. I, if error is less than 002mm. 0001(."), use ratchet stop to lock screw tightly, then use wrench to pull fixed till two lines alignment. II, if error is greater than 002mm. 0001(. "), Step1, use ratchet stop to lock screw tightly, then use wrench to loosen ratchet stop and differential sleeve. Step2, realign- lines of fixed and differential sleeve, then put ratchet stop back on. If necessary, adjust it again using I. Note: There is no need to calibrate micrometer during common use. Micrometer only need calibration when it is severely worn. Package Includes: 1 x Inside Micrometer 1 x Wrench 1 x Calibration 1 x Packing Box Note: Please note that new type and old type of this product will be sent randomly, and sure you will not mind before ordering.