 Aside from his guitar making, he was also the former Director of Engineering at Millenium Cell Inc. and designed and invented hydrogen fuel cells known as Hydrogen On Demand, hydrogen from sodium borohydride generators for DaimlerChrysler.Even after the developing company Millenium Cell closed in 2008, Petillo continued with the product.In the guitar circle, Petillo is most famous as the inventor of the "Petillo Precision Fret."