Discussion: what is this?

I wondered how long it would take anyone other than Dan to ask. It is what purports to be a measurement of my percent body fat, taken before having anything to eat or drink after waking. I succumbed to a discounted price for the measuring device a month or so ago.

is it a caliper kind of thing?

Bioelectrical impedance - absolute accuracy is apparently open to question but there appears to be a consensus that measurements under similar conditions are pretty accurate relative to each other.