Amazon com: stop watt energy saver In many cases (it appears to be a rebranded version of the common “electricity saving box” gadget sold under many different names), often promoted through aggressive social media ads and fake news style pages.
In a typical home (the “power factor correction” effect of a small plug-in box is usually tiny), and it does not magically reduce the kWh usage that your bill is based on. For bigger purchases (many people look for an assessment from an independent consumer organization), so we checked whether any official StopWatt test report had been published by such a body.