Actually it is a “Pulse” circuit using the Badini circuit.
The “Air Coil” is a Solid-State type has a trigger coil, and run coil. The coils will oscillate creating high voltage spikes that will pulse the plates of the charging battery, that actually pulse off the sulphur layering the plates, that then return the sulphur into the battery fluid.
The Badini circuit is a patented Open-Source circuit. It is not able to be sold, but a DIY project that can easily be made at home.
You can also make a rotor type pulse motor using electromagnet coils and magnets on a spinning rotor. They both do the same thing.
NOTE: The type of transistor and diodes used, as well as numbers or run coils will greatly increase the de-sulfating effect and intensity.
If you follow some of his other video’s, you will see how you can make one for yourself. It is a good tool to have before you equalise any Lead Acid Battery !