These are called Green Cat Eye Shells and are brown and white in color. They are flat on one side and rounded on the other. These measure 1/2" to 3/4" straight across. These are not really a shell at all, they are actually a "half round" shell material that certain snails use as a "front door" or "lid" and is attached to the snail itself, the snail can pull it inward and seal the hole so predators can't get to it.
