Freet 4+1 Tarsa Barefoot Running Shoes Lightweight Mesh Upper - Allows air to fully permeate the shoe's interior, promoting a cooler, drier and altogether more pleasant environment. Open Weave Top Panel - Further increases the shoe's ability to breathe. Two Toe Design - Allows the hallux to move independently from the rest of the foot, encouraging a more natural, flexible and therefore beneficial gait cycle. 3mm Midsole Height - Brings the foot as close to the ground as possible in order to emulate a natural running style. TR (Thermoplastic Elastomer) Outsole - Offers superb grip, cushioning and flexibility whilst being robust and more beneficial for the environment than other compounds.