This is a Revere double boiler insert designed for use with the 1930s through 1990s vintage Revere Ware copper-clad saucepans. It will fit a 2 quart saucepan (the insert does not hold 2 quarts), or any pan that is 7-1/8" to 7-5/8" diameter and at least 3-1/4" or more deep. The second photo shows it in my 3-1/2 quart pan. As you can see it works in that size but it isn't a snug fit. The thick stainless steel insert measures about 9-1/2" handle to handle (just over 7-1/2" without the handles) and is 2-3/4" deep.
The stainless steel finish is clean and shiny. There are some shallow stir marks inside. The yellowish color is a factor of the lighting in the photo only, and the insert is shinier and brighter than it appears in the photos.