Feature:1. REPAIR AND GRINDING: Our CNC engraving collets are suitable for clamping grinding heads on a variety of grinding machines, suitable for repairing and grinding tires.2. SPRING STEEL: These CNC engraving chuck spring collets are made of spring steel, sturdy and durable, stable performance, convenient and other features.3. WIDELY APPLIED: CNC engraving collets are widely used in machining centers, general grinding machines, CNC grinding machines, engraving machines, high speed machines and other processing. CNC lathe, tool and work holding engraving machine.4. COMPLETELY HARDENED: Our CNC engraving tapping collets are very durable and strong for your longer term use, the collet set is accuracy ground with a total runout of less than 0.0003.5. HIGH VERSATILITY: The CNC engraving collets are perfect for a wide range of machining applications including boring, milling, reaming, tapping and grinding. Compatible with most rotating tools used in hardware, hobbies, home and more.Specification:Item Type: Tapping Collet KitMaterial: Spring SteelCollet Specifications: d=3x2.5, d=3.5x2.7, d=4x3, d=4x3.2, d=5x4.Package List:5 x Collet Chuck5 x Storage Canister