The device includes {TAIL ~ a pair} of toroid magnets each having {HEAD ~ a north pole} and a south pole 
The device includes { TAIL ~ a pair } of toroid magnets each having { HEAD ~ a north pole } and a south pole
OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH