The Bridgestone J15 Muscle Back (J15MB) Irons are design for low to no handicap golfers. Being forged from premium carbon steel gives these irons a great feel. The J15MB Irons feature an ultra compact head for the ultimate shot shaping and versatility. The J15MB Irons also have a narrow Sure Contact Sole; Bridgestone’s smallest sole, for consistent contact and turf interaction demanded by the best players in the game.