Refresh their memory about the show, what you demonstrated in your booth and why they should pay attention to your product or service.
1234, Main Street
Boston, MA 02123
08 April, 2005
<Recipient Address Goes Here>
I want to thank you for stopping by our booth at <name of trade show or conference> <when it occurred>. Since there were many attendees at the show, I wanted to make sure that all of your questions about our <product/service> were answered.
As you may already know, Abc Company <strong point as a company>. At the show you may have seen <highlight of the trade show booth>. In order to refresh your memory, I've enclosed <enclosed promotional material>.
If you would like further information, or if I can answer any questions, please give me a call at <phone number>. If I don't hear from you, I'll look forward to seeing you at the next <name of trade show or conference>.
encl: <List of enclosed items goes here>