This set of 5 PSD files will allow you to take your own letterhead and envelope designs and quickly create beautiful mockups. Using smart objects all you have to do is paste in your design and it will be applied to the mockup. It’s great for presenting you designs to clients or in your portfolio. This set goes along with the Identity Set Mockup PSDs. These PSDs were created by Mohammad Jeprie.

http://vandelaypremier.com/psd-files/letterhead-and-envelope-mockup-psd/