Newton Running Men's Gravity IV Synthetic-and-mesh Action/Reaction Technology - Newton's patented active trampoline-like technology that reduces energy loss. P.O.P 1 Technology - Open chamber Action/Reaction technology uses isolated and more rigid lugs to increase responsiveness and amplify efficient running. Biomechanical Metatarsal Sensor Plate - Provides support in key areas of the foot. Durable s.h.a.r.c (super high abrasion rubber compound) - On the outsole, this adds durability to the shoe. High-rebound EVA - Offers a more responsive ride by returning energy on each foot strike.