These doors hide farm themed magnets that your little one can move around from door to door. I found this to be a great travel toy. There are magnets that could get lost, however they are not overly small and there are not many of them to keep track of.
The best age for this seems to be 2 to 3 (recommended for over 3 due to possibility of choking, so be careful). Ours has been on several plane and car trips and is still going strong. By the way, this is from Melissa and Doug Toys, so it is sturdy, wooden, and wonderful!