ThomasNetThis website, (free with registration), allows users to find manufacturers, service companies, or product suppliers. It is based on the multi-volume print directory known as the Thomas Register, and it has company listings on over 173,000 U.S. companies, offering everything from filter housings to steel ball bearings. A useful feature is the online supplier catalogs, that provide detailed buying information about a company's products or services; these online catalogs can be searched by company name or product group.