Beryllium Copper Flat Washers Crinkle Washers : Nominal Bolt Size MM Inside Diameter Max Inside Diameter Min Outside Diameter Max (D2) Outside Diameter Min (D2) Height Max (H) Height Min (H) Thickness Nom (T) 1.6 1.8 1.7 3.7 3.52 0.51 0.35 0.16 2.0 2.3 2.2 4.6 4.42 0.53 0.38 0.16 2.5 2.8 2.7 5.8 5.62 0.53 0.38 0.16 3 3.32 3.2 6.4 6.18 0.61 0.46 0.16 3.5 3.82 3.7 6.9 6.68 0.79 0.63 0.20 4 4.42 4.3 8.1 7.88 0.84 0.69 0.28 5 5.42 5.3 9.2 8.98 0.89 0.74 0.30 6 6.55 6.4 11.5 11.23 1.14 0.99 0.40 8 8.55 8.4 15.0 14.73 1.4 1.25 0.40 10 10.68 10.5 19.6 19.27 1.7 1.55 0.55 12 13.18 13.0 22.0 21.67 1.9 1.65 0.55 16 17.18 17.0 27.8 27.47 2.41 2.16 0.70 20 21.21 21.00 34.7 34.31 2.66 2.16 0.70 Available in Stainless Steel and Beryllium Copper (self colour & zinc plated)