Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number GB21A5 found under Heat Sink Electrical Electronic by Nassau Corp. The National Stock Number assigned to this part is 5999013219172, and the Federal Supply Class is 5999 Miscellaneous Electrical And Electronic Components. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like GB21A5.