Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 552-5588539 found under Flushing Block Hydr by Huntington Ingalls Incorporated. The National Stock Number assigned to this part is 4820012474760, and the Federal Supply Class is 4820 Valves Nonpowered. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 552-5588539.