COMPATIBILITY: Designed specifically for OKI ML320, ML321, ML390, and ML391 dot-matrix printer models BRAND NEW: Replaces OKI part number 51902220 ensures perfect fit and reliable performance FUNCTIONALITY: Platen knob enables manual paper feeding and adjustment for precise positioning of forms and documents EASY INSTALLATION: Simple replacement part that can be installed without special tools or technical expertise DURABLE CONSTRUCTION: Made with high-quality materials to maintain smooth paper feeding operation Keep your dot-matrix printer running smoothly with this replacement platen knob designed specifically for OKI ML320, ML321, ML390, and ML391 models. The platen knob allows for precise paper adjustment and manual paper feeding, ensuring accurate alignment of forms and documents. This essential printer part helps maintain the functionality of your printer's paper handling system. The knob provides smooth rotation and reliable control over paper movement, making it easier to load and position continuous forms or single sheets. Whether you're replacing a worn-out knob or keeping a spare on hand, this component helps maintain your printer's performance for business-critical printing tasks. Compatible with multiple OKI printer models, this platen knob is a practical choice for offices and businesses that rely on dot-matrix printing for multipart forms, invoices, and other important documents.