Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number HSB4-218 found under Bearing Sleeve by U S Bearings And Drives Inc. The National Stock Number assigned to this part is 3120000019912, and the Federal Supply Class is 3120 Bearings Plain Unmounted. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like HSB4-218.