Babolat has modified their RPM Blast Formula and created RPM Blast Rough. The rough texture helps increase spin potential in addition to the octagonal shape. The co-polymer mono-filament construction uses a special cross-linked silicone coating ensuring the strings still glide across each other. RPM Blast Rough plays softer than original RPM Blast, with a little bit more pop. This iteration is a wonderful choice for players who hit heavy topspin but want a little livelier feel than most co-poly strings. Construction: Extruded co-polyester monofilament Color: Black, Yellow, Florescent Red Gauge: 1.35mm 15L | 1.30mm 16G |  1.25mm 17G Length:  12.2m (40')   Features: -Octagonal Profile for Spin -Cross-Linked Silicone Coating -Rough Texture -Softer than original RPM Blast