Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number S1RA8-4-3 found under Disk Valve by W And O Supply Inc. The National Stock Number assigned to this part is 4820015863514, and the Federal Supply Class is 4820 Valves Nonpowered. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like S1RA8-4-3.