MR190537-LLB Enduro Bicycle Bearing Abec3 19.05x37x9mm, 3/4"x37x9mm BMX BB

Seals or Shields = LLB = This is a Nitrile material rubber with a steel insert. Rather than the standard 2RS type seal, by machining a groove into the inner race where the seal can rotate with better efficiency and less rolling resistance.