3.5mm Adustable countersink drill bit with a free spinning depth stop for use with the Centrotec system. The Centrotec shank is designed for use with the Festool Centrotec System, as well as with all standard or keyless chucks for no-slip performance. The Centrotec System was designed to provide a seamless transfer of force, eliminating bit slippage or marring of the drill bit. The weight of the drill is reduced by nearly ½ pound, and the length is reduced by nearly 1-1/2" with the Centrotec System. Most importantly, the Centrotec system offers a quicker and more secure means of bit change than any other quick-change chuck system.