Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number HS1551-275 found under Washer Key by Mcdonnell Douglas Helicopter. The National Stock Number assigned to this part is 5310009498026, 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 HS1551-275.