Mermaid bath toys and dolls are made from several plastics and rubbers, including plastic, PVC (polyvinyl chloride), rubber, and polypropylene.
Sizes vary widely, from very small bath pieces to large dolls. Listed heights range from about 0.44 inches up to 14.75 inches, with several mid-sized figures around 2–5 inches.
Battery requirements vary. Some bath toys list 3 AA alkaline or AG10 button cells, some dolls list 2 AAA alkaline (often installed), and many figures note no battery required.
Common play features include automatic LED lights that change color on water contact, color-changing tails (temperature-activated), and larger dolls that play phrases, songs, or sound effects when activated.
Tail features described include color-change with warm or cold water, soft flexible textured tails, and removable or transformable fins/tails that convert for different play options.