Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 803-4384538 PIECE 187 188 found under Bearing Sleeve by Esta Products Co. The National Stock Number assigned to this part is 3120013802566, 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 803-4384538 PIECE 187 188.