Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 7B553 found under Insulator Feedthru by Ngk Locke Inc. The National Stock Number assigned to this part is 5970008524845, 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 7B553.