The new M4 irons are engineered to take you farther and straighter. The duo of RIBCOR and Speed Pocket promote face flexibility for efficient energy transfer at impact and enhanced forgiveness. The Ultra-Thin Leading Edge works in conjuction with the Speed Pocket to increase speed on low-face shots. Optimized heel and toe weighting provides a significant increase in MOI, resulting in more forgiveness. Standard TaylorMade warranty applies and satisfaction is guaranteed.