Last week I momentarily left my 16 week old baby playing with this in his bouncy chair. He started to cry his I've-just-scratched-myself cry, or at least that's what I thought, on my return he had his thumb stuck in the smaller star shaped (purple on our model) ring and was pulling on it with the other hand but was unable to free it. After a quick twist to get it to the right angle we were able to free the little thumb! We treated the swollen thumb at home with cold compress and lots of TLC and by the following morning it had gone down (although still evident). My little one is quite round and so I wouldn't want an older baby that has slimmer fingers and is stronger to cause any more damage to themselves. I have contacted the company but had no response. I think it would be ok to give to a child who's fingers are too big to fit in the smaller rings but hold it back from the advised 3 months+ age suggestion on the product.
For ref:
www.kidsii.com/brightstarts/p-47-grab-spin.aspx