We have a couple of stacker style toys in our house, but this is by far the best. It is comprised of four large and differently coloured and textured star rings (which can be stacked) and a smiling star that sits on the top. The sensor at the top of the toy means that every time a piece is stacked, whether in size order or not, the child gets a rewarding sound and light show. This has made it much more attractive to my daughter, who has just turned a year old.
Recommended, not just by her but also by me because there are fewer pieces to pick up than with similar toys!