The novelty of 3-D printing is now giving way to widespread use by designers. Fenner Drives, Manheim, Pa., makes belts, hubs, chain guides and other equipment parts. The company’s expertise in urethanes led to the development of NinjaFlex® 3-D printer filament, launched in October 2013. The line was expanded within months of its introduction, as manufacturers used it for 3-D printing of everything from bike handle grips to helmet liners to shoes.