Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 20S-1 2-2 found under Beam Hoisting by Caldwell Group Inc The. The National Stock Number assigned to this part is 3940012016885, 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 20S-1 2-2.