Check the listing for details. Gauge block 81 pcs. Grade A+B. Condition: New. Listed at 239.00 USD. Gauge blacks, Standard inch system. Precision grade between B and AParallelism: 0.000005", Maximum tolerance: for size within 1" +0.000008/-0.000004; for size 2" +0.000016/-0.000008; for size 3" +0.000020/-0.000010; for size 4" +0.000024/-0.000012. Calibrated at 20º， made of steel material; Coefficient of thermal expansion: 11.5x10-6 81 sizes are: 0.0500, 0.1000, 0.1001, 0.1002, 0.1003, 0.1004, 0.1005, 0.1006, 0.1007, 0.1008, 0.1009, 0.1010, 0.1020, 0.1030, 0.1040, 0.1050, 0.1060, 0.1070, 0.1080, 0.1090, 0.1100, 0.1110, 0.1120, 0.1130, 0.1140, 0.1150, 0.1160, 0.1170, 0.1180, 0.1190, 0.1200, 0.1210, 0.1220, 0.1230, 0.1240, 0.1250, 0.1260, 0.1270, 0.1280, 0.1290, 0.1300, 0.1310, 0.1320, 0.1330, 0.1340, 0.1350, 0.1360, 0.1370, 0.1380, 0.1390, 0.1400, 0.1410, 0.1420, 0.1430, 0.1440, 0.1450, 0.1460, 0.1470, 0.1480, 0.1490, 0.1500, 0.2000, 0.2500, 0.3000, 0.3500, 0.4000, 0.4500, 0.5000, 0.5500, 0.6000, 0.6500, 0.7000, 0.7500, 0.8000, 0.8500, 0.9000, 0.9500, 1.0000, 2.0000, 3.0000, 4.0000