Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number P99-56 ITEM 11 found under Spring Valve Retain by Elsag Bailey Inc. The National Stock Number assigned to this part is 5360010399525, and the Federal Supply Class is 5360 Coil Flat Leaf And Wire Springs. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like P99-56 ITEM 11.