ALL-CARB 5 Pair of 1-2-3 Blocks Matched Pair with 23 Holes Precision Machinist Milling 0.0002 Inch Milling Machine Jig

Precise - Accuracy with squareness on all sides within .0002 per inch. Cross drilling design gives minimum weight and maximum strength. 23 holes consists of 5 tapped holes that are 5/8-11 for clamping and Holes - 18 untapped holes. Made of precision-grade tool steel hardened and precise ground on all 6 sides of block. Heat treated and case hardened to HRC 57-62.