Picked up these two neat plastic insulators. One at the N.I.A. show (Left) and the other spotted on eBay (Right). First is a CD 155 opaic plastic lookalike marked on the bottom AIROVA//HECHO EN MEXICO. I was lucky to find this piece at the Gettysburg National. Next right picture shows the marking. I had to take a black marker over the letters to make them show up in the photo. Now if I could only get the rubber HECHO EN MEXICO insulator. 2nd is a CD 154 plastic style insulator marked CTM. Not sure what the CTM exactly stands for but closest I've found searching the internet was Continental Tool Mfg. Co. They were railroad related but it's just an assumed guess.