Complete DIY Installation Set: Each component is designed for a straightforward installation process, making it ideal for quick DIY repairs and upgrades on your RV. Universally Compatible & Precise Fit: Engineered to fit most standard RV windows and roof vents, these knobs feature a 1/2inch shaft and a 2-1/4inch diameter. Ensure to check your existing hardware dimensions for a seamless fit, enhancing the functionality and ease of use in your vehicle. Quality Direct Replacement: Replace old or knobs with these high-quality plastic alternatives. Designed to match specifications, these knobs ensure longevity and reliability, maintaining the aesthetic and functional standards of your RV's interior. Ergonomically Designed for Comfort: The knobs are crafted with user comfort in mind, featuring curved edges and a textured grip. This design ensures ease of use and secure handling, preventing slippage while operating window cranks or vent mechanisms. Durable Material for Lasting Use: Made from premium plastic, these knobs resist wear and tear in varied environmental conditions. Smooth, burr-free edges contribute to safety and durability, making these knobs a reliable choice for any camper, trailer, or motorhome. Color: Black Material: plastic Package Contents: 4 x knob 4 x screw 1 x screwdriver Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.