The 4mm Spiral Drill Bit Set with Reusable Centrotec Shank provides a precise, compact, and durable solution for drilling wood, metal, and plastic. Precision-ground HSS steel stays sharp longer for precise hole drilling and a long service life. This set is based on a replaceable drill bit that fits securely into a reusable Centrotec shank for quick and efficient use with the Festool Centrotec Chuck System. The reusable Centrotec shank can also be used with all three-jaw chucks for no-slip performance. Set includes 3 bits, reusable Centrotec shank, set screw and allen wrench.