Kids Helmets

Looking for a helmet for my 1 year old son, he's not climbing, but hangs out at the base and don't want him to get smacked by rockfall. Also getting a seat for my bike that he can ride in behind me, so a versatile helmet would be great. We've been looking at the Petzl Picchu, any reviews on it? Or recommendations for something else?

The petzl is what my daughter uses. It doubles as a bike helmet. I highly recommend it.