Composite outgoing mailer and return envelope form

A one piece form is provided for Z-folding into an outgoing mailer. Upon removal of tear strips from two sides of the outgoing mailer and removable panels, the remainder of the folded form can be made into a return envelope. The composite form uses four panels to define a sealing flap for the outgoing mailer, a contiguous second panel for receiving printed information to define a back panel for the outgoing mailer, a contiguous third panel to define an insert for the outgoing mailer and the front panel of the return envelope and a contiguous fourth panel to define the front panel of the outgoing mailer and eventually the back panel for the return envelope.