a pre - stretched plastic strap is produced for subsequent use in a strapping machine . two mated pairs of rollers are attached to a drive mechanism causing each roller pair to roll at a predetermined rate . each roller pair comprises a nip therebetween , one serving as a brake nip and one the other serving as a tensioner nip . the rolling speed of the tensioner nip is controlled higher than the rolling speed of the brake nip . a plastic strap is conducted through the brake nip and tensioner nip , and the rolling speed differential between brake and tensioner nips causes elongation of the strap conducted therethrough , with the strap having a predetermined tendency to return to its original , unstretched length . this abstract is submitted in compliance with uspto rules , and is not intended to limit or otherwise indicate the scope of the claims .