Size of shank & ColletsQty. & ClampingBack Bar ThreadNT30×ER257PCS(2-16mm)M12×1.75P15PCS(4-16mm)NT30×ER326PCS(6-20mm)M12×1.75P11 PCS(4-20mm)18 PCS(3-20mm)NT30×ER407PCS(6-25mm)M12×1.75P15 PCS(4-26mm)23 PCS(4-26mm)NT40×ER257PCS(2-16mm)M16×2.0P15 PCS(4-16mm)NT40×ER326 PCS(6-20mm)M12×1.75P11 PCS(4-20mm)18 PCS(3-20mm)NT40×ER407PCS(6-25mm)M16×2.0P15 PCS(4-26mm)23 PCS(4-26mm)NT50×ER326 PCS(6-20mm)M24×3.0P11PCS(4-20mm)18 PCS(3-206mm)NT50×ER407 PCS(6-25mm)M24×3.0P Size of shank & ColletsQty. & ClampingBack Bar ThreadBT30-60L×ER168 PCS(3-10mm)M12×1.75PBT30-60L×ER326 PCS(6-20mm)M12×1.75P11 PCS(4-20mm)18 PCS(3-20mm)BT40-70L×ER168 PCS(3-10mm)M12×1.75PBT40-70L×ER326PCS(6-20mm)M16×2.0P11 PCS(4-20mm)18 PCS(3-20mm)BT40-80L×ER407 PCS(6-25mm)M16×2.0P15 PCS(4-26mm)23 PCS(4-26mm)BT40-100L×ER168 PCS(3-10mm)M12×1.75PBT40-100L×ER2011 PCS(3-13mm)M12×1.75PBT40-100L×ER326 PCS(6-20mm)M16×2.0P11 PCS(4-20mm)18 PCS(3-20mm)BT50-100L×ER326 PCS(6-20mm)M24×3.0P11 PCS(4-20mm)18 PCS(3-20mm)BT50-100L×ER407 PCS(6-25mm)M24×3.0P15 PCS(4-26mm)23 PCS(4-26mm)BT50-150L×ER326 PCS(6-20mm)M24×3.0P11 PCS(4-20mm)18 PCS(3-20mm)BT50-150L×ER407 PCS(6-25mm)M24×3.0P