I own a Body-Solid GDCC200 functional trainer. I bought these to use for lying leg curls. I wrap the cuffs around my ankles and then attach them to one of the cable weight stacks. I lie on my stomach and crank out a few sets of curls. The cuffs are very effective, extremely comfortable, and solidly built. I tossed away the basic cuffs that came with my machine since these padded ones are perfect.