I believe this was used in hospitals in the 1950's for hot dishes like soup. This bowl is for an individual serving with dimensions of outside measurements at 4 3/4" diameter and inside measurements at 3 1/2" and stands 2 1/2" tall. I think it is insulated because the walls of the bowl are ¾" deep. It also has a lid that is fairly thick. I have used this bowl with cover and it certainly did keep my food hot.