Just to be double sure, mostly because these no names and the three new Tri M's aren't similar in style to the clearly marked TriM's I already have, I had to check all of the clearly marked Triangle M's. Sure enough, these three are double rested. And finally, just out of curiosity I wondered if the older Illinois insulators (Macombs) had double rests? Only one did, a baby signal (pictured at the bottom of this page). Well, hope this wasn't too terribly boring. I feel fairly comfortable asserting that the double rest is a trait that can be attributed solely to the Illinois Electrical Porcelain Company.