1. Firm clamping: With high elasticity and strong clamping force, the stable spring clamp ensures no vibration or loosening. 2. 13pcs set: There are 13 collets 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, etc. 4. Advanced workmanship: Through exquisite workmanship, has good low temperature impact resistance and high precision, very durable. 5. Easy storage: Each pliers has its own storage box, which adds more convenience to carry for daily use. Specification: Item Type: Spring Clip. Material: spring steel Clamping range: approx. 1~7mm/0.04~0.28inch (1mm/0.04inch, 1.5mm/0.06inch, 2mm/0.08inch, 2.5mm/0.1inch, 3mm/0.12in, 3.5mm/0.14in, 4mm/0.16in, 4.5mm/0.18in, 5mm/0.2in, 5.5mm/0 .22 inch, 6 mm / 0.24 inch, 6.5 mm / 0.26 inch, 7 mm / 0.28 inch) Tolerance: 0.01mm Product quantity: 13 pieces. 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 Storage Boxes. Note: Ask professionals to install.