Manufactured with a non-metallic outer sleeve designed for applications where corrosion or electrolysis may be of some concern. The bearing features a dense outer case structure of engineered reinforced thermo plastic for rigidity and fit. The specially compounded nitrile rubber is securely bonded to the shell with all tolerances maintained to ensure proper lubrication integrity. Johnson employs the highest quality materials that are inherently resistant to all known chemicals, oil and grease to ensure a non-corrosive anti-electrolytic bearing. Johnson non-metallic Cutless brand propeller shaft bearings have full type approval from the American Bureau of Shipping and are available in imperial and metric sizes for shaft diameter from 3/4'' to 6-1/2'' (19.05mm to 165.10mm).