Features Premium 40CR Material: The milling cutter chuck is made of 40cr alloy steel, which is high in hardness, sturdy, wear-resistant and long-lasting. Good Replacement: The balanced drill chuck has fine workmanship and a smooth surface without burrs. It is a good substitute for the old model. Portable: The milling cutter chuck is small in size, convenient to carry, does not occupy space for storage, and is convenient to use. Perfect Application: The BT40‑ER20‑70 CNC tool holder is suitable for ER20‑A chuck, you can choose according to your work needs. Safe to Use: CNC milling cutter has strict quality control and quality assurance, high safety. Specification: Item Type: CNC Tool Holder Model: BT40-ER20-70 Clamping Range: Approx. 1 ~ 13mm / 0 ~ 0.5in (ER20) Length: Approx. 70mm / 2.8in Material: 40cr Package List: 1 x Tool Holder Package List 1 x Tool Holder