I recently got a demonstrator from TW with really textured strings. I asked about them and they didn't exactly know what string was in the racquet. They said they thought it was either RPM Blast 17 or ISOSPEED Baseline Control String 16. Def not RPM Blast, I’ve used that. They were black, thin (seemed 17g), and edges that seemed quite sharp. It seemed square and if I ran my finger across it, it would catch the skin like a knife edge. I don’t see the ISOSPEED in anything but a reel, and I don’t see people talking about it being crazy textured. In searching for this string, I’ve tried Gamma Moto 17 and Solinco Tour Bite. I’ve tried a number of other rough strings in the past. Any ideas? I'd imagine TW has to carry it since they did the stringing.