Dear …
Thank you for the courtesies you extended to me with my visit to your facility __(yesterday/last week/recently/etc.)__. You were very generous with your time and I greatly appreciate the opportunity afforded to me to learn more about your business. I have to say the __(type of )__ facility that you operate is very impressive.
Having now seen the __(plant/process/etc.)__ myself, I believe that our __(type of service/product)__ can add to the __(efficiency/quality/etc.)__ of your __(type of production/task/product/etc.)__. By __(briefly describe how your service/product will help them)__ you should see a difference in __(briefly describe the difference they will see)__. As promised, I’m enclosing __(type of information)__ for your review.
I thank you for considering __(Name of Organization)__ for your __(type of needs)__ and look forward to being of service to you in the future.
Sincerely,