Lurendrejeri.
These "power saving" plugs are widely available on the Internet. The premise is that you plug them into ANY socket in your home and suddenly your electricity bill gets lower. These claims are usually backed up by testimonials from satisfied users who quote staggering savings on their electricity bills.
In reality the plugs have no significant effect on a home power bill, since the only effect they have is random compensation for any continuous inductive loads in the home like transformers in power supplies. But even then, it's just a random correction of power factor (relationship of the voltage waveform to the current waveform) and as this is not even monitored by most household meters it won't have any effect on your bills at all.
https://www.youtube.com/watch?v=1o3mADtThUs