When you need a cartridge bearing, this Enduro Ceremic Hybrid Cartridge Bearing is going to work for you. ABEC-5 Tolerances ensure perfect seating of this 15mm (ID) x 24mm (OD) x 5mm (Thickness) Cartridge Bearing. The LLB seals create a premium protective barrier to keep dust and grim out of the bearing. The Graphite Nylon retainers, Si3N4 Grade 5 Balls and the cryogenically treated races all combine to create an unmatched bearing.