My rats managed to open all the compartments with their claws. The internal space of each compartment is different, some are smaller, but a piece of fruit fits in all of them. All compartments open easily (if it were difficult, the animal wouldn't have the strength to open it). The wood looks like pine (not sure). \n \n I found the finish to be very good, looking very secure. If I had to buy another one, I would take exactly this model. I recommend! \n \n A good entertainment for small animals, just keep in mind that once the animal learns, it opens more easily, but this is a characteristic of all these toys, not just this one.
