The Babolat RPM Rough 15g is a rougher version of the best selling RPM Blast, which will provide increased spin potential. The Babolat RPM Rough 15g features an octagonal section with a rough texture, and cross-linked silicone—producing a unique sensation thanks to the high-density Co-PET. This string is an outstanding choice for heavy hitter looking for the ultimate spin experience. This 660' reel can string between 16-18 racquets. Babolat Tennis String 243136-15