This is a set of two thin blankets. The Aden one is for newborns to around 6 months old, and the petit main one is a thin gauze, size M, which I think is for around a year old and up. They were convenient for adjusting to the temperature, like wearing one by itself in the summer, layering them as a sleep sack in the winter, or wearing one underneath a thicker blanket. I used them for one season.