The Primus Lite 3.5 is our original training all-rounder, reimagined with a new upper to get us closer to circularity. Made for moving naturally and building natural strength during runs and wide-ranging training disciplines, it’s perfect for experienced barefoot cross-trainers and those new to barefoot performance. 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. Breathable Mesh: Breathable, lightweight and comfortable. The Primus Lite 3.5 is a versatile performance trainer for running, cross-training, and dynamic day-to-day living that reclaims your natural potential. It’s wide for natural stability, thin for natural feedback, and flexible for natural movement. We're on a mission to create a fully circular shoe - a new Vivo made from an old one, which can in turn be made into another. The Primus 3.5 is a big step forward on this journey.