Features Made after fine workmanship, inner hole grinding, quenching and hardening, strong and durable. The tool handle has a coated appearance, is rust-proof, wear-resistant and protects the spindle from wear. The tool holder is used for machining CNC machine tools, speeds ≥12000rpm, very convenient. Long-term heat treatment, can effectively remove residual stress during grinding. With long service life, heat treatment with vacuum quenching oven, improve the hardness of the tool holder. Specification: Item Type:CNC Router Tool Holder Model: SK40-ER32-70. Material: 20CrMnTi Hardness: 58±2HRC. Purpose: Used for CNC machining Scope of application: CNC machine tools Accuracy ≤ 0.05 mm. Speeds ≥12000 rpm. Clamping range: approx. 3 ~ 20 mm / 0.1 ~ 0.8 inches. L: approx. 132 mm / 5.2 inches. D: approx. 63 mm / 2.5 inches. d1 Outer diameter of the nut: approx. 50 mm / 2 inches. Package list: 1 x CNC milling tool holder Package List 1 x CNC Milling Tool Holder