Bakelite was patented in1909. These are early1920's bakelite (Bak a lite) door knobs. These knobs are now almost a hundred years old & are quite sought after as collectibles & soon to be antiques, as they turn 100. This was the earliest form of plastic, but much more beautiful. These knobs are amber or butter colored knobs & they look different, according to the light. These sell nowadays for about $100 per pair. The older they get, the better they look, as they gain a patina.