Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 12B-1 found under Clutch Positive Nonvehicular by Hank Thorn Co. The National Stock Number assigned to this part is 3010010796212, and the Federal Supply Class is 3010 Torque Converters And Speed Changers. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 12B-1.