The difference between the older and newer button hole makers is whether or not the machine zigzags. The old ones in the green box plastic box or older do not need a built in zig zag. It moves back and forth. It will work on machines with built in zig zag anyway. The newer ones in cardboard boxes only work on machines with built in zigzag. The box should have a stamped notation for what it works with. The old green box machines to not have markings except by the clamp that goes on the needle bar. It will say straight or slant. Or it will say slant for slant-Matic machines.