packets of prismatic geometry referable to a longitudinal axis , presenting two larger side faces , two smaller flank faces and two end faces , are overwrapped by a method including a step in which each packet , enveloped initially by a tubular wrap projecting beyond the two end faces , is inserted into a holder of a transfer wheel in such a way that two appendages of the tubular wrap projecting at either end from a first flank face of the packet are flattened over the end faces ; the appendages are pinned immediately along two lines coinciding substantially with the corner edges of the end face as the packet enters the relative holder , and held stably in position during a subsequent step of transferring the single packets from a feed station to an outfeed conveyor .