1pc Thread Tapping Screw Die M8x1.25mm 9Si Alloy Steel Durable Round Dies It applied the material of 9 Si alloy steel. its hardness is up to HRC602. It taps quickly, thread grinds accurately, and has long service life. Product Name: Round Die; Dimension: M8 Screw Pitch: 1.25mm; Material: 9 Si alloy steel;Hardness:HRC602; weight:23.75g