A gauss meter probe whose tip senses the magnetic field perpendicular to the probe shaft (sometimes called a flat probe). Best for loops and butterfly coils where the field runs parallel to the accessory surface near the wire. Lay the probe flat along the surface for a clean reading. The Hall element is mounted facing outward from the side of the probe, capturing the tangential field component.
Gauss probes come in two shapes, and the shape sets which way the field must point to be read. A transverse probe ends in a thin flat blade and reads the field passing through the flat of the blade, so it is laid flat to the surface and can slip into edges and tight spots. An axial probe ends in a round rod tip and reads the field entering the end of the tip, so it is held along the axis and pointed straight at the surface. Either shape can measure the field at a surface or in the free space around a coil; the shape only changes how the probe is held to reach the spot.
