Carbon Composite body, steel axle. Aluminum spring axle. S.E.T. (Sensor Elasticity Tuner) allows you to personalize the sensation of float. The three settings provide the choice of more or less resistance within the --5 of angular float. The new ATAC XS arch design keeps your foot centered on the new wider pedal platform for improved foot stability. Self-cleaning mud and dirt cannot stick to the ample 'open arch' engagement mechanism which is wiped clean by the cleat as you step into it. Dependable low spring tension of the patented ATAC design causes less friction in extreme condition, providing consistent entry and release. Easy entry new ATAC XS body profile and new arch design provide even faster step-in. New larger cleat engagement window allows you to concentrate on riding, with no need to focus on aligning your foot with the pedal