The Bluefire M1 Turbo is the hardest and fastest of the Bluefire series. The 50 degree sponge that provides speed and a more linear performance. This means that M1 Turbo produces power in line with what you do with it and put into it. This rubber is designed for aggressive players who can produce full strokes for full power. The turbo version of the Bluefire M1 in high end perfection.