ACB518K (TH073 MR019 MR127) 40 x 51.8 x 8mm 36/45 | Blueseal Bike Bearings™

ACB518K (TH073 MR019 MR127) 40 x 51.8 x 8mm 36/45. Blueseal Bike Bearings™ are bicycle specific bearings. The tighter the seal is to the inner bearing race, the harder it is for water and dirt to get in — and the harder it is for grease to get out.