Found this insulator chunk on the trail today, it's very light blue aqua, this is the skirt of an insulator, roughly the size of a CD 133. The top row of letters has an "E" followed by a "T" and another character of some kind, and the bottom row has a "G". Any ideas?

Edit: Thanks for all the speedy replies! It appears to be a Petticoat H.G.Co. CD 145 from the "G" mold. Not nearly as interesting as we thought it was, but at least we are having fun hunting!