Wilson promises improved power , perhaps more importantly, improved durability with Wilson Extreme Octane 17. Octane has some classic synthetic gut attributes, but it differs in its use of bi-directional ?X-Bands? of Nomex, a derivative of Kevlar more known for its use in fire-resistant suits for race car drivers. That addition enhances durability, elasticity, and resistance to frictional heat. Also, the higher gauge affords added feel.