Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 666231-373 found under Nut Plain Plate by R And N Invesment Properties Lc. The National Stock Number assigned to this part is 5310000064294, 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 666231-373.