Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number SIB-1391 found under Support Waveguide by Sigmation Inc. The National Stock Number assigned to this part is 5985011976984, 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 SIB-1391.