The correct knob for your Greystone gas range models CF-RV17 and CF-RV21 that includes oven temperature markings is available at Elkhart RV Parts. Please review the product photos and description carefully to confirm it matches your needs. To exchange the incorrect igniter/flame control knob you received, you can initiate a return through our online returns portal. Once we receive the returned part, we will process a full refund or exchange for the correct temperature control knob. If you need further assistance identifying the right knob, please provide a photo of your existing control panel. We're here to ensure you get the exact part for your RV range.