I believe this piece to be a possible cap for a wall tube? It's 4 1/4" OD x 4 1/4" tall. Has nice dark old mottled glaze with G. & W. embossed. Beveled on the inside to a 3" ID, then tapers up to the 1 3/4" hole at top. Came from an old substation with some very early pieces. Any information and or ideas as to use or manufacturer would be appreciated.