Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 3M-181 found under Kit O Rings by Metco Inc. The National Stock Number assigned to this part is 5330005666155, and the Federal Supply Class is 5330 Packing And Gasket Materials. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 3M-181.