The Primus Lite Knit shoes have an upper made of extremely breathable knit. This makes this model feel even more airy and agile than the basic Primus Lite version. Vivo Barefoot footwear features all the hallmarks of a genuine barefoot shoe: the sole is extremely thin, and the shoe does not provide support or shock absorption. Additionally, the front part is wide enough to allow the foot to spread naturally with each step. - Normal fit - 2 mm thick Primus outsole - Active Ortholite Performance insole (contains 98% recycled polyurethane) - 0.8 mm thick Pro5 Puncture Resistant layer in the sole structure protects your soles Start barefoot running in small doses - muscles and, for example, the Achilles tendon work in a surprisingly different way compared to using shock-absorbing and stride-guiding shoes. Give your muscles and tendons time to recover!