DONIC BLUEFIRE M1. The BLUE miracle! Bluefire is a completely new rubber development offering top speed. A new high-tech generation of rubbers with the proven Formula FD3-technology has been developed as a result of the perfect combination of the large pored blue sponge with an extremely spinny top surface rubber. The top rubber with its small, long pimpled-in structure increases flexibility and sensational feeling and it features a medium+ sponge density. DONIC Bluefire M1 is a highly suitable rubber for all out attacking players who like to play with heavy topspin and speed.