Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number DB99-0557R1 found under Amplifier Radio Frequency by L3 Communications Dbs Microwave. The National Stock Number assigned to this part is 5996015399296, and the Federal Supply Class is . Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like DB99-0557R1.