Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 25517-21E21ABB2-GBK found under Gage Pressure Dial Indicating by 3D Instruments Llc. The National Stock Number assigned to this part is 6685015493771, 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 25517-21E21ABB2-GBK.