40105-ZZ5-610 Case (Lower) Grom - Overview. The 40105-ZZ5-610 Case (Lower) Grom is a high-quality rubber grommet designed specifically for use in Honda marine engine systems. It supports the lower case assembly by providing a critical seal and cushioning between joined components, ensuring reliable operation and protection from water intrusion and vibration damage. Engineered to meet stringent Honda specifications, this grommet integrates seamlessly with existing parts to maintain optimal system