Large Bursa Crumena shells, Bufonaria Crumena, measure between 3 inches and 3-1/2 inches in size (some may be a little over or under this size range). They are a species of sea snail in the family, Bursidae, the frog shell.  They have a knobby exterior and are tan or brown and white in color. They make great hermit crab homes and are also used in seashell crafts and making seashell ornaments.  Our bursa rana shells are eal - not replicas.  They will have natural imperfections and will vary in size, shape and coloring.