Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 16555-4 found under Collar Strut Pilots by Sps Technologies Inc. The National Stock Number assigned to this part is 1560008390526, and the Federal Supply Class is 1560 Airframe Structural Components. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 16555-4.