APL Athletic Propulsion Labs Men's Joyride Black/Silver Mesh, Hotmelt Propelium is designed to maximize energy generation and provide superior comfort that will maintain midsole structural integrity longer than conventional EVA formulated running midsoles. Midsole/outsole compound developed for direct ground contact, enabling the use of less rubber on the outsole, significantly reducing the weight of the shoes. Inspired by the shape of a feather, the outsole incorporates natural motion flex grooves that react to every movement. Chevron mesh toe box is seamless and expansive, flexing in unison with every movement you make. External heel counter and TPU web provide support to keep you stable and balanced. The 8mm drop from the heel to the forefoot places your foot in a natural position for efficient running.