Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 4392 found under Insulator Washer by Wico Prestolite Co The Div Of Eltra. The National Stock Number assigned to this part is 5970004977838, and the Federal Supply Class is 5970 Electrical Insulators And Insulating Materials. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 4392.