"MR 15307 LLB/LLB" bearing. Best all-steel bearing for wheel hubs. Note that this wheel bearing has a grey "LLU" outer seal that is a medium contact double-lip seal to help keep contaminants out. The black inner seal (faces toward the inside of your hub) is an "LLB" light contact double-lip seal. The internal clearance is a "CN" rating, making it best for lighter press fits.

DIMENSIONS ....... 15mm x 30mm x 7mm
INTERNAL BEARING CLEARANCE RATING: CN
SEALS ...... "LLU" outer and "LLB" inner
BALL MATERIAL .....Chromium Steel
BALL GRADE ............... 5
RACES ........ Chromium Steel
APPLICATION .... Wheel Hub
GREASE ... Realube Bearing Compound