Item Type: End Mill Tool Holder Optional Style: NT40-1-1/2-18 M16, NT30-1-1/2-18 M12 NT40-1-1 / 2-18 M16: Material: High speed steel Connection Thread With Boring Head: 1-1 / 2-18UNF Applicable Machine: Boring machine Inner Hole: Approx. 16mm / 0.63in NT30-1-1 / 2-18 M12: Material: High speed steel Connection Thread With Boring Head: 1-1 / 2-18UNF Applicable Machine: Boring machine Inner Hole: Approx. 12mm / 0.47in Package List 1 x End Mill Tool Holder Please note that the new type and old type of this product will be sent randomly, and make sure you will not mind before ordering. 1Wide application, suitable for various machine tools 2Adopt hardened processing, high hardness and long service life 3Suitable for inner hole iron cutter head, hardened and durable 4Available in two styles for choice: NT40-1-1/2-18 M16, NT30-1-1/2-18 M12 5Made of high speed steel material, durable and long service life