Common safety details to check: BPA-free plastics on some models; mentions of ASTM standards or testing; CPSC choking-hazard warnings on toys with small parts or those labeled for older age ranges. Always confirm the product’s age recommendation and any choking-hazard notices on the label.
Power options vary: some toys need no batteries; many use AA batteries (commonly 3 or 4 AA); a few use button-cell LR44 cells; and some models also support an adapter/USB or power-bank connection in addition to batteries.
Controls range from simple on/off switches to dedicated volume buttons or multi-step volume controls. Many keyboards advertise adjustable volume levels or multiple volume steps (some list examples like 8 levels) and highlight clear, louder speakers for better playback.