You get two pieces (since the 4runner has two cat converters, one on each side, given that it is a V6).
I like them because they are stand alone (the RCI guards require their transmission plate) and they are made from stainless steel, which I like to think would be harder to saw than aluminum.
Truth be known, nothing is absolute. A determined thief with the right tools can breach anything you put in his way. The hope here is that it makes it more trouble for them than it is worth.
Tom's Auto repair pages / tom@mmto.org