32 pcs/set precision metric gage block set, rectangular,DIN861 grade 1--deviation within 0.20um(0.000001m). with serial number and size. Complete certificate of calibration showing deviation of each block. Meets or exceed Fed. Spec. GGG-G-15C and Conform to MIL-STDD-45662A 11 blocks: .1.00 - 1.09mm in 0.01mm steps 9 blocks: 1.1 - 1.9mm in 0.1mm steps 9 blocks: 2 -10mm in 1mm steps 3 blocks: 20.00mm, 30.00mm, 50mm Fitted in heavy duty and precision made wooden box.