Anytime Tools 1-2-3 Blocks Matched Pair Hardened Steel 1 Hole (1"x2"x3") 123 Set Precision Machinist Milling MATCHED PAIR, Professional Quality Tool Precision ground Steel and Case Hardened on all six sides Squareness on all sides within 0.0001" Surface finish from 6 to 16 microinches 1 Hole 0.5"