The 6309 DDU C3 E NSK is a deep groove ball bearing manufactured by NSK and made of bearing steel. It has an internal diameter of 45mm, an external diameter of 100mm, and a width of 25mm. It is designed to be highly durable with enhanced wear resistance compared to other ball bearings. It is double sealed to protect grease from contamination and also features a non-contact rubber seal for further protection. It is suitable for low and medium speeds, and can be used in a range of applications, including in automotive, industrial, and marine applications.