90301-ZZ5-M00 Flange (5mm) Nut - Overview. The 90301-ZZ5-M00 Flange (5mm) Nut is a high-quality OEM hardware component engineered for Honda marine engine systems. It is specifically designed to provide secure fastening with its integrated flange, which improves load distribution and prevents loosening under vibration. This 5mm nut plays a critical role in maintaining the integrity and reliability of the marine rigging and accessory systems by ensuring that connected parts remain firmly in place.