Your mtb is more than just a tool for training; it's an accessory to your lifestyle. You've engineered your life to accommodate your riding, it seems reasonabe to expect the same of your bike components. The REX 1 series is a work of engineering founded upon the principles of lightweight and rigid. We wanted to craft mountain bike cranks that could respond to whatever demands you throw at it. Crank arms CNC-machined in Spain from aeronautic-grade 7055 aluminum are combined with proprietary technologies to yield cranks with an exceptional stiffness-to-weight ratio that can handle the dizzying wattage that you'll stomp out on the REX 1.1 or 1.2.