Looks like one of those carnival "sweaty palms" strength testers
If you can't take it apart, you could at least give the sensors a look... are they metal pads, plastic, actually magnetic sensors...? Put some fields around them and see what shows up on the screen!
Also, not to be confused with actual science: NMR/MRI is the closest real thing to this product's name. Cool stuff, tricky to measure. The Phys Rev papers by Purcell, et al. are classics from the 50s, still a good read today.
Tim