Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number MAC6V40-5450-21 found under Air Conditioner by Trane Us Inc. The National Stock Number assigned to this part is 4120001081747, 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 MAC6V40-5450-21.