Specifications: Type:Micrometer Gauge Caliper Material:Stainless Steel Tungsten Carbide Measuring Faces. Locking Clamp For Positive Locking Of Spindle. Satin Chrome Finish.Constant Force Ratchet Thimble. Supplied With Adjusting Key And Setting Ring. Range:5-30mm Graduation:0.01mm Accuracy:0.005mm Zeroing: Clean The Surface Of Measuring Anvil Heads With A Soft Cloth, Then Rotate Measuring Device To Make Two Measuring Surface Contact. If Two Zero Lines Of Differential Sleeve And Fixed Barrel Do Not Alignment, Use The Following Two Methods To Adjust. Method I, If The Error Is Less Than 0.02mm (0.001"), Use Ratchet Stop To Lock Screw Tightly, Then Use Wrench To Pull Fixed Barrel Till Two Zero Lines Alignment. Method Ii, If The Error Is Greater Than 0.02mm (0.001 "), Step1, Use Ratchet Stop To Lock Screw Tightly, Then Use Wrench To Loosen The Ratchet Stop And Remove Differential Sleeve. Step2, Re-Align Zero Lines Of Fixed Barrel And Differential Sleeve, Then Put Ratchet Stop Back On. If Necessary, Adjust It Again Using Method I. Note: There Is No Need To Calibrate Micrometer During Common Use. Micrometer Only Need Calibration When It Is Severely Worn. Package Include: 1 x Inside Micrometer 1 x Wrench 1 x Calibration Ring