Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 3973120-157215 found under Bearing Half Sleeve by Chief Of Engineers. The National Stock Number assigned to this part is 3120003523160, 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 3973120-157215.