K-2 Meter (K2, K-II)
EMF meters detect electromagnetic fields. When a spirit/ghost manifests, it gives off an electromagnetic field, which may be picked up by an EMF meter.
When a spirit/ghost manifests, it needs energy to do so. In an area where there are high EMF fields the spirit/ghost may draw in that high EMF and manifest. In theory, a spirit can communicate with you through this meter by lighting up the LED lights.