Mizuno JPX923 Hot Metal HL Irons were created to address the issue of increasingly strong lofted irons across the industry. For some golfers, typically those with a slower swing speed, shots struck with lower lofted clubs don't produce enough spin and thus never reach their optimal apex. Consequently, distance suffers, and the ball will struggle to hold the green. HL, or high launch, features a lower, deeper center of gravity and weaker lofts that yield a high, easy launch. Despite this new design, HL Irons retain the same blade length and nearly the same size topline as standard Hot Metal. Introducing Nickel Chromoly – A new material with so much additional ball speed, Mizuno's engineers switched their focus to feel and stopping power. At 35% stronger than our original Hot Metal material, 4335 Nickel Chromoly enables a high-energy 8% thinner clubface. Combined with Mizuno’s vibration controlling V-Chassis and deep CG design, the JPX923 Hot Metal irons are as enjoyable and controllable as they are long. The HL model is a higher launching option for players with moderate swing speeds or aggressive shaft lean. The Combo sets includes JPX Fli-Hi long irons for ease of launch at slower swing speeds.