HEAD recently released the Sonic Pro Edge, an updated version of their Sonic Pro. The Sonic Pro is a cylindrical monofilament. The new Sonic Pro Edge is a five-side geometric monofilament and is made from a combination of resins and fibers, resulting in a unique co-polymer polyester.
What does this mean for you? According to HEAD.com, "this string provides maximum control, more touch and excellent durability. A magnified contact area grabs the ball for maximized spin."
Wondering if this new string is worth trying? The Racquet Sports Industry conducted a string playtest on the HEAD Sonic Pro Edge. In their in-depth review, they mention that they have playtested 168 strings. They found that the "Sonic Pro Edge tied for second for Control, placed fourth overall for Spin Potential, came in 14th overall in Durability, and placed 20th overall in Resistance to Movement. That's four top-20 finishes for a co-polyester string."
I would take that as thumbs up... but you can see for yourself! Read the Racquet Sports Industry's entire playtest review and then do your own Sonic Pro Edge tennis string test!