This one also exposes some other scams.
In the US, in addition to KWH industrial sites may also meter KVAR - reactive 'power'. Power factor correction, matched to the reactive load, can save a lot of money at those sites. Reactive 'power' is not metered for residential and these black boxes for residential are a scam.
Some of these scams say (or imply) that the reactive 'power' registers on a utility KWH meter - a lie.
A couple others: "SAVE UP TO 25% ON YOUR MONTHLY ELECTRIC BILLS!"
"Who Else Wants To See Savings of Up To 15% Off Their Home Electric Bills?"
================= The same type of scam as the Iraq IED "detectors" were sold in the US. Basically a fancied up dowsing rod 'detected' drugs and other items. There were interchangeable modules to detect different things. They were bought by police departments, schools, .... Exposed on one of the TV news magazines like 60 minutes. I believe the US government put them out of business.
I think many millions have been spent on the scam used in Iraq. Sold out of England?
============================== Some of the clip-to-your-fuel-lines-to-save-gasoline scams were just "cow magnets".
-- bud--