Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number HCS1004-021 found under Filter Direct Current Power by Heatcon Composite Systems Inc. The National Stock Number assigned to this part is 5915016641985, and the Federal Supply Class is 5915 Filters And Networks. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like HCS1004-021.