Brass shell metric sized bearings offer strength, durability and longevity. This brass will not corrode and is a strong shell that will last. It is also easily replaceable. These shells are approved by Lloyds and are precision ground inside and outside Nitrile Liner. They have Outstanding abrasion resistance, are Excellent for water lubrication and have Good noise damping. They are more tolerant of misalignment and allow greater deflection Shell: The Brass Shell (standard naval brass) - tough and durable.