Made of Quality Alloy Tool Steel Grade EN31 instead of Mild Steel. Read material characteristics of EN31 & its advantages over Mild Steel in description below. Size of the block is 1" x 2" x 3. Total 23 Through Holes being done in 1 operation (5 tapped drills 3/8 x 16 TPI & 18 plain drills). Drilling & Tapping done on computer controlled Vertical milling center to avoid sloppiness & misalignment. The squareness and parallelism is controlled well within 2-3 microns. Deep Hardened, Matched Pair, Precision Ground, Even Chamferring on all 6 sides. These matched pair can be bolted through any plain hole to the tapped hole to use as a Steps blocks, feelers, Jigs, Angle plate, orientation and setting up tool. This item is in the category "Business & Industrial\CNC, Metalworking & Manufacturing\Metalworking Equipment\Metalworking Lathes". The seller is "globaltools2016" and is located in this country: IN.