You're shopping for a full-body PEMF mat, and the spec that jumps out is the coil count. More coils sound like more field. But a count is a headline, and it leaves out two things that shape what your body actually gets: whether the coils fire all at once or one at a time, and how evenly the field is spread across the surface. Two PEMF mats holding the same six coils. On the left, all six coils fire together. On the right, the coils are numbered one through six and fire one at a time, with only coil one…

You're looking at two discs the same size, and their peak Gauss values aren't close: the bigger one is over four times the smaller. It's tempting to read the bigger number as the stronger device. But both came off the same device. The coil inside the disc, not the device's power, set the peak. A disc is just a housing. The coil it holds might be a pancake, a donut, or another shape entirely, and from the outside two discs can look the same. What you can't see is the wire inside, and that's what shapes the field. Two measured…

You place a disc's center over a small joint, run the full session, and the relief comes up short. With a pancake coil, that's usually a placement miss. With a donut coil, the placement itself is the miss: you've aimed the field's weak spot at the joint. Two discs can share the same outer size and housing and still deliver very different fields. The coil wound inside sets the field's shape. A pancake concentrates its strength at the center. A donut spreads its strength into a ring and leaves a dip in the middle. A cross-section of a donut coil…

When you place a disc on a knee for a 40-minute session and the patient feels less relief than expected, the instinct is to blame the device. Placement is the more likely culprit. A brochure can list peak Gauss without saying where the field is strongest. That value alone doesn't tell you where to place the disc. Two discs of the same outer size can deliver very different fields. A pancake coil peaks at the center; a donut coil peaks in a ring around the center. A cross-section of a pancake coil drawn beneath a field-strength curve. The spiral winding…