Purchased a couple of these for my children , my daughter in particular is unable to use a traditional mask and pipe because it makes her gag... saw these and had to give it a go! This is a brilliantly designed mask, I got her a small/medium and after some small adjustments it fits perfectly and comfortably and worked perfectly underwater, we tested it in the bath first! keeps the water out whilst allowing her to have excellent vision and also enabled her to breathe whilst having their face submerged.
We had a holiday In Spain and they took a bit of space in the case but for the fun that they had made it worth it.
A very good purchase and something I would recommend to anyone going on holiday or planning to go snorkelling.