Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number B43S6MM found under Valve Ball by Swagelok Ltd. The National Stock Number assigned to this part is 4820013790367, 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 B43S6MM.