Jason Day, a PGA TOUR player, recently switched to Srixon ZX5 MK II long irons (3 and 4) and Srixon ZX7 MK II mid-to-short irons (5-PW) to improve his iron play. Day, an equipment free agent, made the switch before the Texas Children's Houston Open in search of lower spin rates, which he believes will help him achieve greater control, especially as a high-ball hitter.Day had previously tested the Srixon ZX7 irons but only had one club at the time. He experienced inconsistent spin with his previous irons, leading him to give the Srixon ZX7's another shot. He is also pairing his new Srixon irons with his familiar, extremely stiff True Temper Dynamic Gold X7 shafts, which are renowned for their spin-killing properties.Day's decision to switch to Srixon irons is primarily due to his concerns over his spin rate, which he believes is excessive and affects his control, particularly with his high-ball hits. The Srixon ZX5 MK II long irons and Srixon ZX7 MK II mid-to-short irons are designed to provide skilled players more distance, forgiveness, and workability while maintaining a clean and compact shape.In summary, Jason Day's switch to Srixon ZX5 MK II and ZX7 MK II irons is a strategic move to improve his iron play, reduce spin rates, and gain better control over his high-ball hits.