The Centring Piston is the innovative centring system for CORONA TRE 300 ASPIRAZIONE core bits. Suitable for diameters below 112, it keeps dust extraction effective even when inserted in the connection, i.e. at the start of drilling. The bayonet coupling makes insertion and subsequent removal quick and easy. It is important to remove it from the connection as soon as the core bit has cut its own seat, i.e. after just 0,5/1 cm of hole depth, to avoid damaging it and/or unnecessary strain.