The MR104 is a precision-engineered, single-row miniature ball bearing designed for mechanical configurations where internal space is strictly limited and operating speeds are exceptionally high. Characterized by its unshielded, open architecture, this 4x10x3 mm component offers zero seal-induced friction. It allows the direct flow of external lubricants, making it an indispensable part for internal assemblies, sealed gearboxes, and oil-bath environments where external contamination is already managed by the main housing.