Hollow irons offer a sleek, narrow look along with the forgiveness you ™d typically only expect from larger designs. ZX4 Irons deliver an exceptionally good address profile while also boasting our most powerful forgiveness to date. It ™s a game-changing combination that makes Srixon irons accessible to a whole new class of players that prefers game improvement equipment. TECHNOLOGY: MAINFRAME - A milled pattern on the backside of ZX4's face maximizes COR for more ball speed and more distance on every shot. HOLLOW DESIGN - ZX4's hollow design gives you enough forgiveness to strike the ball across the face while still enjoying high shots that fly straight and find their targets. MULTI-PIECE CONSTRUCTION - Tungsten in the base of ZX4's long and mid irons (4i-7i) lowers its center of gravity for a higher launch. A forged HT1770 Steel face enhances speed and distance while a 431 Steel body absorbs vibration for softer feel. TOUR V.T. SOLE - V-shaped soles glide smoothly through turf, even if you strike slightly behind the ball. ZX4 Irons also feature the resurgence of our popular sole notches. PROGRESSIVE GROOVES - Grooves in the 8i through PW are sharper, narrower, and deeper for more spin and stopping power on approach shots into the green.