Titleist 591 5-P 6-iron set, a legendary club. The utility club in the photo is also included. Shaft: Onoff Labospec LABO SPEC KICK ST90 (FLEX has R and S, but this feels like R) #5/404g From an article review: Titleist 591 Forged Irons Made with a focus on feel above all else. The unique design improves the feel by giving thickness to the sweet spot. The neck shape is semi-goose, and the center of gravity is lower in the long irons, making it easier to catch the ball and get it airborne. From the manufacturer's article: Repulsion Kick ST90 A high-precision, club-specific steel shaft developed with the concept of "flexing and repelling." The grip section has high rigidity for a "firm feel," while the tip section has a "flexing feel," allowing for a sharp swing-through and acceleration of the clubhead.