Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 73-13521-DC found under Switch Proximity by Topworx Inc. The National Stock Number assigned to this part is 5930014141287, 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 73-13521-DC.