Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 04121-440 REV.B found under Switch Electronic by Barco Simulation Llc. The National Stock Number assigned to this part is 5930015191291, and the Federal Supply Class is 5930 Switches. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 04121-440 REV.B.