Altra Rivera 4 Running Shoes The Altra Rivera 4 is for runners looking for a go-to neutral shoe for daily mileage or as part of their active lifestyle. Engineered Mesh Upper Utilising a mesh upper, the Rivera 4 works to keep your feet cool and comfortable, by allowing a constant supply of airflow. The materials are also moisture-wicking, meaning sweat and moisture will be efficiently wicked from your feet, and dispersed through the construction of the material, therefore enhancing in-shoe comfort, and keeping your feet dry. This lightweight, low-bulk upper keeps you light and comfortable on your feet, for undistracted performance. The shoes utilise Altra's Slim FootShape Fit technology to allow your toes to relax and spread out naturally for more comfort and stability in uphill climbs and downhill descents. To further keep your feet feeling fresh, the shoes have a breathable tongue that sits flat against your foot and a revamped heel collar to help prevent irritation a