The portion of a multi-coil mat surface where the magnetic field exceeds a defined fraction of the peak. Reported in cm² and as a percentage of total mat surface at two thresholds: 50% of peak (the therapeutic core area) and 10% of peak (the practical edge of useful field). Coverage tells you how much of the mat actually delivers meaningful intensity rather than fading between coils.
A mat spreads many coils across a wide surface, and each coil lays down its own field footprint. How many coils there are is the coil count, how they are arranged is the coil layout, and the surface they cover together is the coverage area. When every coil peaks at about the same strength the coverage is uniform, and the field that spills from one coil into its neighbor is neighbor coupling.
