Confidential Covering Letter
This Confidential Covering letter provides for a description for the project/target, and instructions that none of the enclosures are to be shown to third parties. A copy letter should be included for signature by the recipient.
However, it is probably advisable to have a full confidentiality or non-disclosure agreement agreed between the parties before releasing any sensitive information. A number of agreements are available at Consulting and Confidentiality
This Confidential Covering letter template is in open format. Either enter the requisite details in the highlighted fields or adjust the wording to suit your purposes.