The Babolat RPM Team Comfort String Set is a new co-polyester and is a more comfortable alternative to RPM Blast. Features micro air bubbles into the string permits for additional flexibility. Still very durable. Suits big hitters looking for extra spin. Octagonal (8-sided) cross-section adds extra bite on the ball for added topspin and slice. If you enjoy RPM Blast who wants more comfort and feel, the RPM Team is a great fit.