Tough casing, soft core! The Babolat RPM Blast Rough is extremely resilient and guarantees variety rich tennis. Technically the Babolat RPM Blast Rough is a Co-polyester string. It lends your racket ultimate spin and assists you to find creative remedies for tight situations. The octagonal cross section is designed for hard base line duels and gives you the power and touch in decisive moments for the winning shot. A big plus point. Due to its rough structure the RPM Blast Rough is terrific for creating twist. Make you play unpredictable with the Babolat RPM Blast Rough. Highlights: A spin happy string for ambitious players and a multi faceted match. More twist, more power, a great feeling. Less string abrasion. Resistant Co-polyester with rough structure and inter laced silicone.