Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 1259T 4BB 300 found under Valve Pressure Blan by Circor Aerospace Inc. The National Stock Number assigned to this part is 4820011943584, 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 1259T 4BB 300.