M4 2021 Irons Ultra-thin Leading Edge Works in conjuction with the Speed Pocket to increase speed on low-face shots. Heel and Toe Weighting Optimized heel and toe weighting provides a significant increase in MOI, resulting in more forgiveness. Fluted Hosel Fluted Hosel and 360º undercut allows for redistribution of mass low in the head to increase launch distance, and consistency. M4 2021 Hybrid Split Mass Pads Two internally split mass pads that increase inertia to deliver more ball speed across the face. Two-tone Crown Two-tone crown cosmetic in a low profile shape provides a confidence-inspiring look. Speed Pocket Increases flexibility and distance across the face. Low-face strikes will be rewarded with the improved Speed Pocket by preserving ball speeds for consistent distance.