Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 657D138-006 found under Bearing Assembly by Timken Gears And Services Inc. The National Stock Number assigned to this part is 3120001152742, 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 657D138-006.