Magic Tricks

That depends on what you're trying to accomplish.
Look at this as a great utility that gives you many options regarding a switch.
A Mercury fold could be used in some routines, but it isn't required in all routines.
For example, have a spect sign a card, fold the thing right in front of them and use your favorite vanish to make it disappear.
Seeing the clip off to the side the whole time, or in a jar, just bring the clip into play, do your switch and bring your vanished, signed card back for the spectator to see/verify.
Ta da!

Thank you - that is very helpful. I will order it today!

If you're pre-scared of the Mercury fold, you could try the pre-scored solution.