THIS BEARING IS 1mm DIFFERENT FROM 6903-2RS AND USED IN MANY HUBS. THE ORIGINAL BEARING QUITE OFTEN HAS 61903 ON THE SEAL - CHECK YOUR INTERNAL DIA, THIS HAS 18MM (61903 CAN ALSO BE 17MM INTERNAL DIA WHICH IS 6903) Generally seen on DT Swiss hubs

• Part Ref: MR18307-2RS
• Bearing ID: 18mm
• Bearing OD:  30mm
• Bearing Thickness: 7mm
• Material: Chromium Steel GCR15 (Race & Balls)
• Used On: DT Swiss Hubs
• Grease: SINOPEC HTHS Bearing Grease, 30% filled
• Seal: Double-sealed 2RS