Two detail views of the BJ-4 Drawtwister used during the early stages of nylon production and research at the DuPont pilot plant in Wilmington, Delaware showing the relocation of the draw pin string-up. The photographs are captioned "left side position--figure 4" and "right side position--figure 5," indicating that they appeared in a report or publication.

As part of the cold-drawing process, drawtwisters were used to stretch the nylon filaments following extrusion. As visible in the photograph, the machine primarily consisted of draw rolls that ensured the filaments were stretched uniformly before being wound onto bobbins.