original or mailed copy to bear the original information marked on both sides and a retained two sided copy bearing a copy of the same information as is recorded on both sides of the original referring now to fig4 and 6 the alternative embodiment illustrating the application of the invention to a duplicating form to provide an original bearing the original marking on both sides and a copy with a copy of the information recorded on the original is provided as in the previously described embodiment a pressure sensitized sheet and a carbon sheet are utilized in the preparation of two sided copies which in this embodiment utilize one additional guard sheet in this embodiment of the invention as illustrated in fig4 and 6 the original of the duplicating form 40 may be a postal card with a fold 42 or of a single split sheet construction not shown with a split or separation between the layers to form a single package duplicating form in either application of the invention to this embodiment the original sheet has a front side fig5 amp 6 41 and a back side 52 to form an envelope enclosing a carbon sheet 44 a single file copy sheet 46 having a tab 48 disposed thereon to assist in its removal and a guard tissue 50 the single package duplicating form 40 contains a cutout portion 54 through which on the back side 52 will protrude a portion of guard sheet 50 and on the front side 41 will protrude a portion of carbon sheet 44 to facilitate in removal of.