Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number SP421 found under Cover by Fluid Conditioning Products Inc. The National Stock Number assigned to this part is 2945006310124, and the Federal Supply Class is 2945 Engine Air And Oil Filters Cleaners Aircraft Prime Moving. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like SP421.