There are two sides for the coils, one is smooth and the other is bumpy. The coils must always have the smooth side touching your skin. There are three different ways of using the coils.The first way is to have the coils side by side. This increases the area being treated, but the treatment depth is shallow.
The second way is to have the coils acrossed the treatment area, so the coils face each other. In this way, every part between the coils will be treated.
The third way is to stack them on top of each other. In this way, the bumps of the coils face each other. This is similar to the side by side coils, but the depth is increased.