Nothing as scientific as an inductor! Some guy took the Tellus to bits. This is actually discontinued, but the Tellus II is £1380.
Basically it is some black granular stuff and some random bits of metal - brass strips with notches on the edge and some aluminium plates and sheet. And the construction standard of the box is horrid.
https://www.facebook.com/media/set/?...2581122&type=3
Wow. Just wow.