40107-ZV5-820 Case (Lower) Grom - Overview. The 40107-ZV5-820 Case (Lower) Grom is a genuine Honda marine engine system component designed to protect and seal vital parts within the lower engine case. This rubber grommet supports the rigging system by providing a secure, waterproof passage for cables or hoses, preventing water intrusion and damage to internal engine components. Precisely manufactured to meet factory specifications, it ensures seamless integration with existing parts, maintaining