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.