Head Gravity is a very innovative hybrid. Unlike the majority of hybrids, this one features two poly-based strings. The main string is a triangular shaped co-poly that is designed to put a tight grip on the ball. The cross string is a very slick, round co-poly that enables the main strings to move out of position and snapback viciously to produce heavy spin. A great option for the player who wants maximum spin combined with exceptional precision and durability. Ideal for strong intermediates and advanced players with long, fast strokes.