Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number S2173 found under Restrictor Unit Flu by Tactair Fluid Controls Inc. The National Stock Number assigned to this part is 4730007249325, and the Federal Supply Class is 4730 Hose Pipe Tube Lubrication And Railing Fittings. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like S2173.