You can use 20-gauge wire or smaller with the Regular Wubbers Looping Pliers. We do not recommend using larger wire because it can damage the small round jaw of the pliers. Twenty-gauge wire is the perfect fit for the Regular Wubbers Looping Pliers–the space inside the jaws is large enough so that the wire is not damaged, but small enough to grip the wire so that it is stable and does not slip and slide around as you work with it.
I love working with 24-gauge balled head pins, and they do slip and slide inside the jaws of the Regular Looping Pliers, which I find frustrating. However, there is a very easy solution! There is a product called Finger Pro Tape that is made of a thin gauze that is coated so that it self-adheres, making it super easy to use. It is thinner than the medical tape (which is important!) and much less expensive. It is only $2.00 per roll, lasts forever, and is so easy to use!