Dear
It was a pleasure speaking with you today and as I promised, I am enclosing literature on the (products). It will give you an overview as well as complete details of all the products.
I will be happy to get together with you, upon your request, to explain the functions of each system in order to assist you in your decision making process.
Thank you for the courtesies you extended during our telephone conversation. I hope that we can help you fulfill your requirements.
Cover Letter Product Literature in Response to Phone Inquiry