ESP stands for Extraordinary Spin Potential. I strung up my Blade (my regular stick) with kevlar/ZX at 63/49 (both pre-stretched manually). Combining: a) large difference in stiffness between mains and crosses b) with a 14-lb differential in tension c) on a low-friction setup... ...yielded a result that was nothing short of amazing. The stringbed was firm and crisp with perfect directional control and depth control on volleys and flat shots. But the mains are free to travel laterally and snapback better than in any setup I've used previously. When I wanted to spin the ball heavy on serves or forehands (or outside-in bh slices), the spin was as heavy and extreme as the spinniest shaped poly. But it does not have the high launch angle of other spin-friendly setups. And when I wanted something in between flat and heavy spin (like a finesse topspin lob to the backhand corner), I got the trajectory I wanted there too. The "dynamic range" of the stringbed is something I've never come close to with any conventional setup. I chewed the fuzz off two balls (the only downside I've noticed) hitting against the wall for an hour (where I added a couple grams to the tip to make up for the lost SW of the 1/16" shorter hoop), then played a couple hours of doubles outside. Really enjoyed being able to use my complete game by having a such a versatile stringbed. Serves were great too. My ESP sees kevlar making a comeback soon, with more people going to extreme tension differential between mains and crosses. One interesting thing that is noticeable, comparing a full poly stringbed to this one: When I pull a main string laterally on the full poly bed, the (positive) resistance force when stretching is much greater than the (negative) resistance when allowing the string to return. In otherwords, much of the snapback force in the full poly stringbed is offset by the friction between the strings. In the high stiffness ratio, high tension differential stringbed, the snapback force has minimal friction resisting it.