A secondary receiver coil is sutured around the iris.
From the en.wikipedia.org
But electric toothbrushes transfer power only from the primary coil to the secondary one at very close range.
From the sfgate.com
Previously, the suppression has been carried out by positioning an iron barrier or a set of secondary coils outside the main coil that produces the original unshielded field.
From the sciencedaily.com
A fully denatured protein lacks both tertiary and secondary structure, and exists as a so-called random coil.