I saw these a few weeks ago, and asked a friend who is a metallurgist and spends some time in mines. He has some calcium carbide head lamps that he keeps running as a curiosity. He says the shipping on calcium carbide will eat you up. It's a hazardous substance, so there's a pretty steep base price for shipping. The only way to get it at any decent price is to order a whole lot of it, which is pretty expensive.