Forums: Discussions for entrepreneurs and small business.

I've spent a lot of time researching my product, patent option (including an initial search), drawing specs, and I've just recently purchased material to make one or more working prototypes. I am targeting a very specific group of end-users and have a niche' that no one else has developed in this market area. I want to put together a complete Profile and have all contemplated questions answered should I choose to have the product Licensed. Here's my issue....I'm definitely not sure where I should start looking for the market research....I'm looking for some specific stats (how many possible customers there could be). Anyone have advice?