Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 1AT89A2-1-2 found under Synchronizer Unit A by Porta Drill Inc. The National Stock Number assigned to this part is 2520006892975, and the Federal Supply Class is 2520 Vehicular Power Transmission Components. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 1AT89A2-1-2.