Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 1644 MB found under Valve Ball by Dean And Wood Ltd. The National Stock Number assigned to this part is 4820011121799, 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 1644 MB.