4mm Centrotec Spiral Drill Bit provides a precise, compact, and durable solution for drilling wood, metal, and plastic. Manufactured from HSS steel which is precision ground for precise hole drilling. HSS steel is high quality steel that stays sharp longer. This bit has been designed to incorporate a replaceable drill bit within the Centrotec shank for use with the Centrotec chuck. The Centrotec shank can be used with all three-jaw chucks for no-slip performance or in conjunction with Festool's Centrotec chuck system. With the Centrotec design there is a better transfer of force with no chance for bit slippage or marring of the drill bit. Reduce the weight of the drill by nearly ½ pound and the length by nearly 1-1/2” with the Centrotec system. Additionally the Centrotec system offers a quicker way of changing bits than a keyless chuck with less run out. Replacement HSS Spiral Drill bits are available and are economically packaged in 10 pc packs. The replacement bits are all precision ground and polished and can be used in wood, metal and plastic. Set contains 3 bits and Centrotec shank holder, set screw and allen wrench.