Morse Marine Bearings require no seals, oil or grease for lubrication. They are lubricated by water and are maintenance free. Rubber-lined naval brass sleeve bearings adapt well to strut and stern tube mounts. The external brass shells are machined and polished to provide easy fitting. The standard flanged series outer shell is made of centrifugal cast naval brass. The highly durable rubber liner resists abrasion caused by particles in the water and is oil and chemical resistant. The resilient rubber also helps dampen noise and vibration. Using water as a lubricant makes the bearings environmentally friendly and it provides low-friction operation as well as stable operation because of waters incompressibility. Key Features: Rubber lined Water lubricated Environmentally friendly Oil and chemical resistant Rubber liner dampens vibration and noise Outer shell made of naval brass or non-metallic compositeParts Selectorsnewcontent.westmarine.com/documents/pdfs/OwnersManuals/ENGINE_SYSTEMS/Morse-NonMetalicSleeve.pdfnewcontent.westmarine.com/documents/pdfs/OwnersManuals/ENGINE_SYSTEMS/Morse-StandardBrassSleeve.pdfnewcontent.westmarine.com/documents/pdfs/OwnersManuals/ENGINE_SYSTEMS/Morse-StandardFlanged.pdfnewcontent.westmarine.com/documents/pdfs/OwnersManuals/ENGINE_SYSTEMS/Morse-StandardMetric.pdf