Feature: 1. Firm Clamping: With high elasticity and high clamping force, the stable spring clamp ensures no vibration or loosening. 2. Pack of 13: There are 13 collet chucks in the set, which allows a wide clamping range from 1mm to 7mm, very useful. 3. Wide utility: suitable for ER tool holder, extension rod nut, collet drill, boring tool, carving tool, reamer and so on following. 4. Advanced workmanship: Thanks to fine workmanship, it has good low temperature impact resistance and high precision, very durable. 5. Easy storage: Each pliers has its own storage box, adding more convenience to carrying for daily use. Specifications: Item Type: Spring Clamp Material: Spring Steel Clamping Range: Approx. 1-7mm/0.04-0.28in (1mm/0.04in, 1.5mm/0.06in, 2mm/0.08in, 2.5mm/0.1in, 3mm/0.12in, 3.5mm/0.14in, 4mm/0.16in, 4.5mm/0.18in, 5mm/0.2in, 5.5mm/0 .22in, 6mm/0.24in, 6.5mm/0.26in, 7mm/0.28in) Tolerance: 0.01mm Product quantity: 13pcs Scope of application: Suitable for ER tool holders, tool holders, extension rod nuts, collet drills, boring tools, carving tools, reamers. Package List: 13 x Spring Clip 13 x Storage Box Note: Ask professionals to install it.