Newton Running Women's Aha II Synthetic-and-mesh One-piece Seamless Engineered Mesh Upper - Breathable and chafe free upper for an extremely comfortable and distraction free fit. Action/Reaction Technology - Newton's patented active trampoline-like technology reduces energy loss. 5-lug P.O.P 3 Platform - PU foam backed chamber derived from Action/Reaction technology offers a softer ride whilst still encouraging forefoot running. Biomechanical Metatarsal Sensor Plate - Provides support in key areas of the foot. Durable s.h.a.r.c (super high abrasion rubber compound) Outsole - Located in high wear areas of the shoe, this adds durability to the shoe.