Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 121B564H01 found under Adapter Sleeve Bearing by Spencer Industries Inc. The National Stock Number assigned to this part is 3110002257793, 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 121B564H01.