Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number MD43S1D-1 found under Attenuator Variable by Herley Industries Inc. The National Stock Number assigned to this part is 5985012559616, and the Federal Supply Class is 5985 Antennas Waveguides And Related Equipment. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like MD43S1D-1.