It is important to attach the case in to chain coupling. 1. When using at high speed. 2. When using in abrasive environments like dust and grit. 3. When used in corrosive environments, such as moisture. 4. Fully lubricates and significantly the extends life of the coupling. 5. Prevents scattering of lubricating agent, and also prevents intrusions, such as dust. 6. Protect body from corrosive atmospheres. 7. Smartens up exterior appearance on top of protecting from danger.