i used to play in the pond across the road as a little tyke. the best way i can describe the stuff in this insulator is a swatch of frog eggs going up side, over dome, and some back down the other side. Kind of a milky swatch with carbon dots in it, and carbon line trailing down other side.

perfect drips and dome. a wire rub of about 1/2 inch takes out part of '89' in the patent date.

$25 plus shipping.