Yes, It worked for me.
I have had an old similar version for many years, and a more recent one.
An advantage is that it can be put at the outlet, or at the end of an extension cord.
Use one at each end of a 100 foot #18 extension cord, when you plug in a portable electric heater.
Or leave the extension cord coiled and see how much additional heat comes out of the wire coil....but I do not advise doing it for long, on your living room floor.

Keep a electrical fire rated extinguisher handy!
Rod J