The O-Ball is great for a three to four month old baby. Because so it can learn grasping excellent and has many little holes definitely a sense of achievement. No matter where it attacks, it gets its fingers in any case in the O-Ball and can hold quite a while it even. The ball is also very flexible but not too soft. So it does not hurt the little one even if it is part time knock on the head or abdomen - which indeed often times happens at that age. After the fourth month, my little one, however, has lost interest. Nevertheless: Highly recommended!