Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number BS-R4CD found under Washer Spring Tensi by Bearing Engineers Inc. The National Stock Number assigned to this part is 5310011143812, 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 BS-R4CD.