Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 3503 found under Coupling Half Quick Disconnect by Schrader Bridgeport International. The National Stock Number assigned to this part is 4730009185125, 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 3503.