Observe: When you enter keyword "6303RMX" into eBay or Amazon, you will notice The supply of OEM dimensions bearings - 10X42X13. "6303RMX" is stamped over the OEM idler #2 bearings. I have robust doubts about these currently being high-quality bearings, including the Koyo bearings labeled as becoming manufactured in Japan https://iodirectory.com/listings13232564/detailed-notes-on-bill-collection-services-in-anaheim