Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number HLK TA BU2 1 1 2 found under Valve Regulating Temperature by Aerco International Inc. The National Stock Number assigned to this part is 4820011420257, 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 HLK TA BU2 1 1 2.