Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number MS21902W12 found under Nipple Boss by Sae International. The National Stock Number assigned to this part is 4730004516046, 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 MS21902W12.