Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number A-204 TEST GAUGE found under Test Gage by Hydro Test Products Inc. The National Stock Number assigned to this part is 5210011496681, 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 A-204 TEST GAUGE.