Abstract: A unit set or assembly of several superimposed parts form a mailer without a stub, folded and detachable glue flaps being provided respectively along opposite sides of the first and second parts from the top, the flaps underlying and being secured to the last or bottom part of the assembly. Three-part or four-part mailer constructions are provided wherein the topmost part comprises a cover ply which, when removed, permits the assembly to be used as a mailer since the second part is secured to the fourth part in a four-part construction by means of glue from the first part flap extending through holes provided in the third part to thereby secure the second and fourth parts together. In the three-part construction, holes are provided in the bottom part so that the glue from the first part flap may extend therethrough so as to secure the second and third parts together.