Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 551-142 found under Filter Radio Frequency Interfere by Wiltron Co. The National Stock Number assigned to this part is 5915013284580, 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 551-142.