Engineered for internal mechanical assemblies where external sealing is provided by the housing, the 6921 Open is a high-performance thin-section radial ball bearing. Completely unshielded and unsealed, this open-type configuration allows for unrestricted flow of fluid lubricants directly into the rolling elements. Because there are no physical barriers or rubbing seals, the 6921 Open achieves absolute zero shield-induced friction, ensuring optimal thermal dissipation and maximum rotational efficiency. It is the ideal component for heavy-duty 105mm shaft applications enclosed in oil bath environments, such as industrial transmissions, large centrifugal pumps, and enclosed machine tool spindles.