Made of natural materials Wonder Shell provides beneficial minerals and electrolytes to aquarium water. Each shell oxygenates aerates and neutralizes harmful acids in your aquarium water and provides invertebrates with an easily available source of calcium for healthy shell growth. Molded like a scallop shell Wonder Shell's decorative shape fits right in with the rest of your aquarium's decor.
Rivers to Reef says:If you have low KH and/or acidic water your snails might be paying for it by having their shells slowly eroding. It is easiest to notice on snails with a dark shell (small pits forming). These wonder shells are supposed to help with that problem. Slowly dissolving and releasing calcium into the water. They also make your "fish have more sex vigor" according to the package. Tell your friend, whom you are asking this question for, they are not for human consumption.