Abstract: A two-way envelope made up from a one piece blank comprising front and back panels joined along three sides thereof to form a container. A first sealing flap is joined along a perforated line to the free side of the front panel and a return sealing flap is joined along a first fold line to the free side of the back panel. The front panel is preferably larger than the back panel, and the front panel is formed with a fold line space a predetermined distance from the perforated line so that the distance from the outer fold line to the bottom of the front panel is greater than the distance from the bottom to the top of the back panel.The return sealing flap is inwardly folded upon itself to permit a larger return flap to be carried within the envelope during the first mailing. At least one crimped portion is provided in the return sealing flap to facilitate the handling of the flap by the first addressee.

Abstract: An envelope for two-way mailing having opposed front and rear panels secured together around three sides to provide an open edged pocket, a first flap to seal the pocket is foldably carried on the edge of the pocket by one panel. A sealing flap is carried on the edge of the pocket by the other panel. The resealing flap is inwardly folded upon its panel and disposed within the pocket during the first mailing. A spot of adhesive at each end of the resealing flap between the said flap and its panel, adjacent the open edge portion of said panel, prevents the resealing flap from being severed from the envelope by the improper insertion of a letter opening device.