Features: Spring steel material, for extra long lifespan, good flexibility and resistance to abrasion. Clamping force, high accuracy, good gripping stability. CNC router tool Adapter to meet your need; simple construction,nice operation. Commonly used in the engraving machine spindle motor folder knife, with the engraving machine collets use. Solid hardened steel bodies with anti-kickback design. Build-up & heat resistant for teflon coating. Specifications: Material:Stainless Steel Size:As Picture Shown Length:Acout:3cm Package Includes: 13x Adapter Collet note: 1.Please allow 1-2cm errors due to manual measurement, make sure that you do not mind before you order. 2.Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thanks for your understandings.