The pin-on type is the rarest of luminous disks. So rare that I didn’t have a picture of it. But you could find one in Michel De Trez’s “The Point Of No Return”. Instead of the clip, it has a kind of safety pin at the back. I am told that these were not marked ‘poison inside’, but that they have the broad-arrow mark. That would label them as British issue, or so I thought until Joseph Muchanski sent me photos of his luminous disk with a pin back. It is not Broad Arrow marked but marked R.L.I. 1942. Under the pin is Pat. # 2336969. It is 1 1/2” in diameter. At first I tried searching the patent number, but I couldn’t find anything. That’s because it’s not a US patent number. The disk is not US but Canadian made. RLI stands for Radium Industries Limited.
See photos below and the updated luminous disks article.
|Pin-on type front (click image to enlarge)||Pin-on type back (click image to enlarge)|