Belden made an earlier design (for rubber rationing days) that utilized a composite insulation that made for a very heavy and stiff cord. The plug had either "Belden" or "Kirby" embossed. The same gauge and design were used on Oster hair clippers and massage instruments in the forties. The more streamlined version appeared in the late fifties with the grey with red ends design. There were some really pretty G.E. plug cords used as well. The extra long cords came in the late fifties also.