Courtesy reply mail, or CRM, is a type of mail in which a business sends pre-printed, self-addressed envelopes or postcards to customers, who then affix postage stamps to the envelopes or postcards and mail them back to the business.http://pe.usps.gov/text/dmm200/additional3.htm "Encouraging Customers to Reply", from the USPS Alternatively, the business can disseminate the envelopes or postcards with stamps already affixed, similarly to metered reply mail.