Listings commonly label floating bath toys from newborn up through about 4 years — typical examples include newborn+, 18 months+, and 1–4 years (infant and toddler ranges).
Most float toys are made from plastic; other materials noted include EVA foam and polypropylene, and some designs combine plastic with small metal components.
Many listings advertise solid or sealed constructions, air- or water-tight designs, and quick-drying or easy-to-clean surfaces — all intended to limit trapped water and reduce mold or mildew buildup.
Yes — at least one toy description notes a temperature-sensitive disc that reveals the word HOT in white at about 104°F, intended to warn if bath water is too hot.
Descriptions include magnetic fishing sets with bobbing characters and linked-boat sets where boats connect to form a small train or chain.