The new wilson staff ci9 irons have a tour inspired shape which includes a thinner topline and moderately progressive offset in a midsize head the exo skeleton surrounding the rear cavity places weight to the heel and toe for a higher inertia moment and greater stability a one piece soft response insert concealed in a soft 431 stainless steel to deliver satisfying sound and crisp feel at impact the wilson ci9 4 sw irons set contains 8 irons 4 5 6 7 8 9 a putting wedge and a sand