Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number GT 304 3 3 8" X 3 8"T found under Sightglass Borosili by Ernst Flow Industries Inc. The National Stock Number assigned to this part is 6680002295578, and the Federal Supply Class is . Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like GT 304 3 3 8" X 3 8"T.