Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number CR4155B found under Nut Self Locking Pl by Alcoa Fastening Systems Ltd. The National Stock Number assigned to this part is 5310143500815, and the Federal Supply Class is 5310 Nuts And Washers. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like CR4155B.