Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 1B4M31 found under Washer Flat by Diamond Reo Truck Co. The National Stock Number assigned to this part is 5310001884175, 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 1B4M31.