Fowler's Metric Bore Gage Setting Master Kit Fowler's new Bore Gage Setting Master Kit is used for accurately setting any bore gage up to 6"/150mm in diameter to an accuracy of .0001"/.003mm Setting Device Features... Base anvil: 2.750" x .80" Adjustable anvil 2.375" x .375" (two each) Internal capacity: 6"/150mm Depth capacity: 1"/25mm Centralizer capacity width: 2.625"/66.7mm Quick-release holder for fast adjustment. Economy Gage Block Sets Metric model: 33 piece AS-2 grade Certificate of Calibration to N.I.S.T.