The Tarmac SL features one of the lightest frames, forks and cranksets in the world thanks to Specialized's FACT (Functional Advanced Composite Technology) AZ1 Technology. AZ1 is a curing and molding technique that combines several monocoque structures so that they become as one. This technique has proven to yield the highest strength-to-weight ratios possible and it produces the ultimate combination of lateral and torsional rigidity and vertical compliance. In short, the S-Works Tarmac SL is the finest-riding bicycle Specialized has ever built!