The Bluefire M3 has the softest sponge. The speed it can produce is surprising with such a soft rubber. The soft sponge allows for a long dwell time and can really charge up a ball with strong topspin. Though lower in speed relative to the other Bluefire M rubbers, its short game is noticeably great, allowing the player to include spin and placement with quality. Recommended for those players who like soft rubbers.