How an energy saver / power saver works?

In India, a lot of multi level marketing companies were promoting a product called energy saver or power saver. It is claimed that by just plugging it in a power circuit, the electricity consumption goed down any where between 20% to 50%. Whether this product works? What is the principle behind it?

karnuvap8 years ago
Big Clive has the answer to this - basically they are a con. They do not work and even if they were wired up correctly (see the link for what I mean) they would only slightly 'fool' the electricity meter to run a bit slow - but they don't actually 'save' any power.
here's the link
rsk115848 years ago|66%3A4|39%3A1|293%3A1|294%3A200

in the above link you can find the product, it is just like some box which is to be plugged in to plug point, what my question is , how can the instrument save power, because it is just plugged into plug point and not into mains, so instead of saving power the instrument itself will consume electricity,
lemonie8 years ago
It could be nothing and do nothing.
It could be some kind of inductor
Those are my best guesses.

rickharris8 years ago
Not sure have you an address of a web site to show one of these? In the UK the power saver strips detect when the PC is turned off and turns off all the other sockets as well so nothing sits on stand by all the time. This saves power. BUT so does switching off manually.