Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number HS3028-4 found under Washer Spring Tensi by Mcdonnell Douglas Helicopter. The National Stock Number assigned to this part is 5310013062219, 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 HS3028-4.