Common features include multiple textured surfaces or nubs for gum contact, internal squeakers or rattles, lights or simple music on some models, and easy-to-grip shapes (handles, loops, or curved designs) to help babies hold and explore the toy.
Suggested ages vary by product: some list ‘Newborn’ or ‘Newborn and up,’ many use 0–12 months, and others span broader ranges such as 0–36 months or labels like ‘3 months and up.’