87 Piece Grade JIS 1 Metric Rectangular Gage Block Set ~ Supplied in a fitted case. ~ Meets or exceeds the JS Standard. ~ Each block has a series number. ~ Made of the highest quality tool steel. ~ Includes 9 blocks from 1.001-1.009 with a step of 0.001mm, 49 blocks from 1.01-1.49 with a step of 0.001mm, 19 blocks from 0.5-9.5 with a step of 0.5mm, and 10 blocks from 10-100 with a step of 25mm. ~ See attached chart for accuracy.