"Package of Two" Smith Corona DX-2600, DX-3400, DX-3500, DX-3600, DX-4000, DX-4400, DX-4500, DX-4600, DX-5000 and DX-6000 Typewriter Ribbon, Correctable, Compatible Black Correctable Film Compatible Replacement For: Part #21000 Package of Two Swartz Ink Products Ribbon