Lotto Raptor Ultra IV Tennis Shoes - White/Aviator - Mens Synthetic Upper: Padded tongue and heel collar enhance instep comfort. Side stability support ensures correct support for the foot during sideways movements. Midsole: Reactive insole aids circulation and the absorption of lactic acid. ReactiveArch moves in unison with the natural deformation movement of the transversal arch in the forefoot, offering greater energy return. Syn-pulse offers differential cushioning between instep and outstep. Removable insole. Outsole: Puntoflex allows the foot to flex correctly and gives excellent elastic return. Longlast 40 rubber compound with high abrasion resistance guarantees a longer lifespan on all playing surfaces.