Many coils in a pad. Each makes its own field; together they cover a large area. The Setting picker steps through four field strengths, so the reach of 25 Gauss can be compared against 100 Gauss. Drag to rotate, scroll to zoom, and use the layer controls to compare depths. Use the picker to switch between settings.
Illustrative example: a representative 3D field for a Multi-Coil Mat, shown to illustrate what this coil type looks like. It is not a spec for a specific product. The four settings are one measured mat scan presented at four drive levels, since a coil driven harder makes the same field shape at a higher amplitude. The 50 Gauss rung is the measured one.