Enduro MR17287 17x28x7 ABEC 3 bearing

Our most popular seal type, this is a Nitrile material rubber with a
steel insert. Rather than the standard 2RS type seal, we go a step
further by machining a groove into the inner race where the seal can
rotate with better efficiency and less rolling resistance. Rather than
one thick seal lip rubbing on a blunt surface, LLB type utilizes two
razor thin sealing lips riding in the groove with light contact. The
outside lip keeps the water and contaminates out, while the inner seal
retains the grease for smooth function and long intervals between
servicing.