Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number X31-131-R found under Socket Wire Rope by Esmet Inc. The National Stock Number assigned to this part is 4030003162484, and the Federal Supply Class is 4030 Fittings For Rope Cable And Chain. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like X31-131-R.