Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number TWE120B 300A found under Air Handler Special by Trane Co The. The National Stock Number assigned to this part is 4120013865447, and the Federal Supply Class is 4120 Air Conditioning Equipment. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like TWE120B 300A.