Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number PS520-100621-03 found under Keypad Control Communicator Prog by L 3 Communications Mapps Inc. The National Stock Number assigned to this part is 6350016131611, 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 PS520-100621-03.