Metric Aluminum multi-hole reference standard. Contains 11 hole sizes; 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, 17mm, 18mm, 19mm, and 20mm hole diameters. EDM notch = 0.5mm x 0.5mm deep corner EDM notch in each of the Countersink Holes, 1mm x 1mm corner EDM notch in each of the through Holes and a 0.5mm x 0.5mm throught the thickness of each hole. 4 Rows total, 2 countersink Rows and two Non-Countersink Rows for a total of 44 holes. Material: 6AL-4V Titanium. 10mm Thick. Includes Test Report and Certificate of ConformanceTraceable to NIST.