NIKE Golf Vapor Pro Combo 4-AW Iron Set - Stiff Modern Muscle geometry balances the CG in the center of the face for maximum ball speed, the highest stability, and the purest feel Ultra-fast Spring Steel faces amplify ball speed RZN cavity long irons (4, 5, 6, 7) and muscle cavity short irons (8, 9, PW, AW) for the superior combination of stability and shot-shaping workability Weight distributed for high-flying long irons and piercing short irons Progressive sole widths with a beveled leading edge for forgiveness and enhanced versatility