***NEW*** TPU Cage - A one-piece translucent heel to mid-foot fit cage that locks the foot down, creating a more stable experience. ***UPDATE*** Extended TORSIONÂ® System - For energy return in the forefoot and natural integrity in the midfoot. Flexible Textile Upper - The textile upper is lightweight and is able to adjust to the shape of your own foot ensuring a comfortable fit. TechFit Upper Support - The seamless upper is supported by TechFit material, which offers you a flexible yet secure feel around your entire foot. ***UPDATE*** Energy Capsule Boost Midsole - Every step becomes charged as the Boost midsole absorbs some of the energy from your footstrike and charges it into forward momentum. The Boost 2 features a greater energy return.