The lightweight SFB B2 is designed for speed and flexibility over rough terrain. The rugged sole is equipped with an aggressive traction pattern and sticky rubber for multi-surface grip, while an internal rock shield helps prevent punctures. And Nike Air cushioning in the heel keeps you comfortable no matter where your adventure takes you. Benefits - Leather and nylon canvas provide durability and breathability. Dual-zone lacing integrates with a durable webbing system for enhanced stability and a secure fit. Shallow flex grooves are anatomically placed, letting your foot move naturally while preventing debris from sticking. Zoom Air cushioning helps provide a quick-off-the-ground sensation. Product Details - Foam midsole. Rubber outsole.