There are many forms of directories out there. Zycon is an industrial directory dedicated to helping out industries on both sides. Zycon is an industrial directory connecting engineers and technical buyers with companies products and/or services. For example if a technical person is looking for stainless steel tubing all he needs to do is to go to zycon.com and get into products and click on rubber gaskets.
The website is easy to navigate with lots of information about the product that you would like to find. A good website optimization makes it rank well in search engines. I have found it better than the other similar directories like Thomasnet or GlobalSpec.