The Qi irons by TaylorMade are a hollow head design with stress on hitting the ball straighter by controlling the flex of the face at impact and do away with the cut shot, a persistent problem for recreational players. The heads are built targeting forgiveness and distance with the proper launch and spin for that loft. The sister model Qi HL is for slower swing speeds and is lighter with stronger lofts. 7-club set graphite shafts $1100