If you look real close you can see the spout were the water goes in and it also has a stainless steel screw on top, the whole underneith is stainless steel, with talking to my mother who is 89 she said it was been around for about 80 years, maybe that is why there are no markings on the bottom, possibly worn off if that is possible. The only markings found were on the cover which could have been from another item and just used to keep the food warmer my mother was not sure on that. Thank you for any input you can give me, it is greatly appreciated.