Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number FF-S-611A found under Spike Track Square Shank by Federal Specifications. The National Stock Number assigned to this part is 2250001994532, and the Federal Supply Class is 2250 Track Material Railroad. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like FF-S-611A.