Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number SFI-500B-2 found under Indicator Sight Liquid by Dwyer Instruments Inc. The National Stock Number assigned to this part is 6680014751826, 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 SFI-500B-2.