Abstract: A die that may be rotated relative to a die holder to form an opening in different types of envelopes, cardboard boxes or other type of blanks or webs is provided. The window opening in an envelope blank is formed by using a sheet of material having a top surface and an outer periphery. A raised portion extends from the top surface of the sheet and includes a cutting edge adapted to cut the envelope blank to form the opening. A coupling means are included to selectively couple the die with the die holder in at least two orientations so that the position of said sheet may be changed relative to the die holder to alter the location in which said cutting portion forms the opening in the envelope blank.