Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number AK221 found under Adapter Hoisting by A And K Mfg Co Inc. The National Stock Number assigned to this part is 3940005298720, and the Federal Supply Class is 3940 Blocks Tackle Rigging And Slings. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like AK221.