24810-ZW7-U01 R (Inner) Housing - Overview. The 24810-ZW7-U01 R (Inner) Housing is a critical component within Honda marine engine systems, specifically designed for the lower unit gearcase assembly. This housing supports the internal mechanics of the marine propulsion system, helping to protect and secure vital components such as the water pump and gear mechanisms. As an integral part of the marine gearcase system, it ensures seamless integration with existing parts, maintaining optimal perform