Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number FR1-4K28 found under Bearing Ball Annular by New Hampshire Ball Bearings Inc. The National Stock Number assigned to this part is 3110009489353, and the Federal Supply Class is 3110 Bearings Antifriction Unmounted. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like FR1-4K28.