Anytime Tools Angle Block Set 30-60-90 & 45-45-90 Precision +/- 20 Seconds, Machinist Tool, 2 Piece Set High Precision: +/- 20 Seconds, 0.0001" per inch Set contains two angle blocks: one 30-60-90 degree block and one 45-45-90 degree block Precision Ground Solid Hardened Steel Thickness 0.25"