Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number SS21B136 found under Spring Flat by G E C Marconi Avionics Ltd. The National Stock Number assigned to this part is 5360999644341, 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 SS21B136.