When I was shopping at Babies R Us I saw this in the infant section and I couldn't resist (David shook his head). I count it with helping Willow to LOVE belly time. Before she could roll front to back, she would lay on this toy and play for quite a while. (And by quite a while I mean 10 minutes or so)
They have a "boy" version (seen here) but that is not available though Amazon.
I really can't say enough how much Willow loved this toy. She doesn't use it anymore since she rolls both ways now, but I definitely credit it with helping to develop her arm muscles. We have since donated it to her Day Care for smaller infants to make use of.