ITEM NAME:New 12Pcs ER16 Spring Collet Set For CNC Milling Lathe Tool Engraving MachinBSE Features: 1.Durable and practical. 2.Special angled slots increase rigidity. 3.Protects tool holder from contaminants. 4.Better overall balance of tool holder assembly. 5.Use with any standard ER collet chucks for coolant-thru tool applications. Specifications: Model: ER16 Precision: