Flexion Fit upper - Proprietary upper which provides form fitting comfort without sacrificing support. Seamless upper - Reduce risk of rubbing and discomfort. P.H.F (Personal Heel Fit) collar lining - For a snug, customised fit. PGuard toe protector - Enhanced toe durability. Solyte midsole - A lighter weight midsole compound than ASICS' standard EVA and SpEVA. Also features enhanced cushioning and durability.