LIGHTWEIGHT AND BREATHABLE SHOES FOR PREMIUM PERFORMANCE AND SUPPORT The Nano X4 Training Shoes are the lightest and most breathable iteration yet of the beloved Nano franchise. These women's Reebok training shoes have been completely redesigned to eliminate any components that might get in the way of elevated performance. An all-new FLEXWEAVE upper is ultralight and a midfoot panel keeps the air flowing. Premium support comes from the innovative Lift and Run Chassis system, while Floatride Energy Foam cushions every stride, making these shoes the ultimate training partner.