This is partly tongue in cheek, but this product is interesting
If you have to ask how much it costs, you can’t afford it 
Is this similar to the chip detectors found in the gearboxes of large helicopters?
I don’t think so. I don’t know what the big helicopters use but since they have had this for years it is probably just a pair of contacts which get bridged by debris, and light up a lamp in the panel.
The product at the top is something much more clever which doesn’t appear to trap the debris but detects it while flowing in the oil.
I am not sure whether an online sensor like this gives you a significant edge over a ground-based one. And ground-based X-ray spectrometric analysers (that’s the usual technology for engine oil analysis) can be bought for a very reasonable amount of money – less than €1000 for a used serviceable instrument. It would certainly pay for itself at any large flying club, school or maintenance facility.
