This 6903-2RS 17x30x7-millimeter sealed ball bearing has deep groove geometry for high speeds and supporting both radial and axial loads. Its premium steel construction makes it resistant to corrosion and high temperatures and it conforms to ABEC 5 precision standard for performance within a narrow range of variation. The rubber seals on both sides of the bearing keep lubricant in and contaminants out. The silicon nitride ceramic balls provide high durability, low density, high shock tolerance, and resistance to heat and fracturing.