8pcs. Set includes the following collet sizes: 3/32", 1/8", 3/16", 7/32", 1/4", 5/16", 11/32" and 3/8" Unique self-releasing system eliminates sticking. For machining tools such as end mills, drill bits, reamers, etc. Flute holding capability for the highest concentricity and clamping power Accuracy to 0.0004". Run-out Tolerance: 0.0004". The thread for an R-8 drawbar is 7/16(.4375) x 20 tpi. The actual runout is 0.00031" Versatile Clamping Range: Includes 8 ER16 collets (3/32"-3/8") for reduced changeover, enhancing efficiency in diverse milling/drilling tasks. Precision Engineering: Offers unparalleled accuracy up to 0.0004", ensuring optimal workpiece alignment and surface finish. Self-Releasing Design: Innovative system prevents collet sticking, facilitating smooth and reliable tool changes. Enhanced Concentricity: Flute holding capability maximizes clamping power and concentricity, vital for high-quality machining operations. Comprehensive Kit: Comes with R8 shank, ER16 collets, non-slip spanner wrench, and a fitted case for organized storage and transport.