Altra Black Paradigm 4.5 Guide Rail Size 10 Excellent used condition The Altra EGO™ midsole gives you performance and cush while the knit upper brings you endless comfort. StabiliPods™ for a stable platform and a GuideRail™ system for support just when you need it most. Asymmetrical design and medial flaring lateral, this shoe offers increased for weak or tired feet, and is great for both neutral runners and those looking to upgrade from over structured "traditional stability" options.