I am not that familiar with this piece, but I am making the assumption that this is a transformer bushing. This one is 6 3/8" tall and 3 5/8" in diameter and weighs 2 pounds, 4 oz. Stenciled on the "front" of this at the bottom (as displayed in the picture) is written "SET GAP 1/2" ". You may be able to see this in the photo. On the back side of this at the "top" end there may have been an arc over, as the glaze is roughened there. I can supply an photo on request. The CD 106 is not included in this sale, but is intended to provide an easy reference to the size difference between them. Asking $10.00 plus actual shipping to your location.

Many thanks to Dustin Logan for providing this helpful information regarding this piece:

I suspect that the bushing in your photo is actually from an old "Frankenstein" knife switch---used in an old powerhouse or substation. Four of these would have mounted the switch to the wall, which would have been pulled by hand. These were once common, in lower voltage applications, like 600v trolley feeder circuits.