Abstract: There is disclosed an envelope that is constructed to allow it to be printed using a minimum of modifications to a printer. To achieve this, a leader extension is attached to the envelope by a novel perforation that is more readily severed, and features are included to allow flexure of the envelope around the curved surface of a support drum of the printer. One of such features that permits this is slits formed within a portion of the overlapping edges of the side and bottom panels. Another of such features is the scoring of the central and/or bottom panels to cause the pocket formed by these panels to flex towards the axis of curvature of the drum.