Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 438 10 found under Valve Steam by Bureau Of Mines Helium Operations. The National Stock Number assigned to this part is 4820009638599, 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 438 10.