Get out into the wild, the barefoot way. The Primus Trail Knit Firm Ground is a minimalist men's running trainer that keeps feet protected and connected. Primus Outsole: Get as close to the ground as possible. Performance Insole: The Performance Insole is made of 98% recycled polyurethane foam, which helps reduce waste and the use of virgin plastics. Tough Rubber Compound: Strong, non-marking rubber compound for sticky grip and high-abrasion when you need it most. Vegan: The main materials in all our Vegan products are synthetic and are not derived from animals. The Primus Trail Knit is an evolution of the Primus Trail FG: our original trail-running sneaker. It features a knit upper for enhanced breathability and purer trail mobility, made with recycled materials, and a sock-like construction to keep out trail debris.