Magnaflux Pie Gauge Magnetic Field indicator Magnaflux| 12754 Magnaflux Pie Gauge Magnetic Field indicator Print Magnaflux| 12754 Magnaflux Pie Gauge Magnetic Field indicator Device to help determine the direction of magnetic fields. Typically used with dry powders for yoke inspection. MG50: Pie gauge field indicator. 169799: Pie gauge field indicator – Magnaflux. Request for information