This is a 4 count wholesale flat of unpolished thunderegg halves from Baker Ranch, New Mexico that were collected over 40 years ago.
Sizes range from 4.25" to 6.25" in diameter. Each thunderegg half is worth between 95 to 110 dollars as is. I averaged them to $100 x 4 = $400. Polished, each half will sell for double to triple (retail price). I think the pricing is fair on this flat with the free shipping!
