When you combine adizero, BOOST, and a need for the extreme, you get Adizero XT Boost. With the protective sock extension, and tire-inspired TRAXION outsole, your grip will be sure and your feats mighty. Upper: Compression collar prevents trail debris from touching your skin. Midsole: Pro-Moderator - thin TPU film on the heel for extra stability. Midsole: BOOST offers endless energy in the mountains and high adaptability on rocky surfaces. Outsole: Continental rubber race king inspired lugs for extraordinary grip in racing conditions. Material: Textile.