For anyone interested, I have walking foot on my website
www.thequiltgal.com and I have been using one just like those on my Featherweights since 1999 or 2000. No problems! Love it!
This is the one in the box in the first picture. See the little fork with the black covering. It goes over the screw that you use to tighten your needle.
The second type are for sale, but NOT on my website. They have the little arm that goes on top of the screw (not a fork over and under). This type does not work as well and as for as I know actually sells for more.