What a great design. I can almost see the boss coming into the Telechron model shop at 4:05 on a Friday asking for a lighted commercial clock. The engineers, in disgust, grab a 1F312 and a gooseneck lamp off the desk saying, "Fine. He wants a lighted clock. No trouble at all..." drill, drill... hammer, hammer... Voila! The 1L312 with time to spare yet!