For years the monofilament string market has been dominated by polyester — a substance that can be too firm and underpowered for less advanced players. About a decade ago, Ashaway’s Steve Crandall began working on a new concept: a monofilament control string with genuine comfort and power, closer on the stiffness spectrum to natural gut. In the early part of 2012, after years of testing and tweaking, Crandall finally found what he was looking for. It’s called MonoGut ZX. The ZX stands for Zyex, which is a much softer and more responsive material than polyester. On his most recent visit to Tennis Warehouse, we had the chance to interview Steve about his impressive new string. Here is what he said.