Vintage Brass Kaleidoscope, "Brass Marblescope" By Artist Doug Johnson.
Here are the Dimensions
over all the kaleidoscope is 7 inches long approx with a marble inside the holder.
the brass barrel is approx 1 3/8 inches in diameter
the marble is an American made 7/8inch diameter marble Bu Either Jodi Fine or Cuneo Furnace both California Artists.
I think this holder is nice and solid and holds the marble well. I think the marble could be up to 1 inch in diameter if you had another marble you wanted to try.