Dear ...
We were very happy to learn that you have referred our __(company/products/services)__ to __(name of company/person)__. Thank you for this great endorsement, giving us the opportunity to gain the confidence of another potential customer. You can rest assured, __(name)__, that we will go to lengths to ensure that we provide top notch service to __(name of potential customer)__.
We are very pleased to enclose our __(brochure/catalogue)__ outlining the various __(products/packages/services/etc.)__ that we currently offer. Each of these __(services/products)__ has maintained a successful track record with our __(customers/clients)__ over the last __(# years/months/etc.)__ due to __(briefly explain why)__. Please feel free to pass this __(brochure/catalogue)__ along to __(name of company/person)__ so that __(they/he/she)__ may browse through these __(services/products)__ at __(their/his/her)__ leisure.
As you know, we have a team of experienced professionals available to answer any questions that __(name of company/person)__ may have. Please encourage __(them/him/her)__ to contact us at __(phone #)__ should __(they/he/she)__ have any questions at all. We would welcome the opportunity to be of service to __(them/him/her)__.
Thank you once again, __(name)__, for taking the time to refer this potential customer to us. We extend our deepest gratitude to you.
Sincerely,