Genuine OEM Oki Microline 621 Toners

The Microline 621 takes a 44173404 black ribbon cartridge. During installation, its knob should turn only in the marked arrow direction to remove slack; OKI warns that turning it the other way can jam the ribbon.

Toner Buzz carries genuine OKI 44173404 black ribbons for the Microline 621 as individual cartridges. Keep an unused ribbon in its packaging until it's time to install it.