Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 8500 AND 8539 found under Gage Brake Drum Micrometer by Hennessy Industries Inc. The National Stock Number assigned to this part is 5210008619117, and the Federal Supply Class is 5210 Measuring Tools Craftsmens. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 8500 AND 8539.