This is one of two known in the hobby (as far as I remember) and I believe it came from a power station in Montana. I finally decided to part with it and if you are going to Yuma, now is your chance. It contains 4 R5050 standoff insulators and about 10 pounds of copper for the knife blade and contact. The marble block probably weighs around 60-70 pounds and is 15"x15"x2". My price is $5000, cash only no trades and I will not ship. I live in the Phoenix area . Sorry for the late posting but just remembered this in storage.