Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 503-3-4M1ALT1ITEM20 found under Spring Helical Comp by Eaton Corporation. The National Stock Number assigned to this part is 5360004212174, 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 503-3-4M1ALT1ITEM20.