Great chamber. Large size mask is too big for a 5 yr old. But you can attach your own smaller one.
Leve had this diamond chamber before and it works well for my 7 yr old. It came with a large sized mask. It is too big for my 7y old. He is average sized. We use a medium sized mask. The large mask advertised that it is for a 5yr old to adulthood. It is too big.