I have not had the chance to try the mask in real conditions. I bought the smaller size at the back end of last summer, but it was too late for my holiday. When evaluating the mask again I felt it to be too small, so I ordered the larger size. Still have not tried that on holiday. The masks seem a great concept & my reason for 4 stars was the washer where the snorkel meets the mask snapped (my fault) I tried to purchase a replacement, but was told that Decathlon don't do spares. Fortunately I bought a product in Primark which had 2 plastic elastic bands, these fitted perfectly. Had it not been for this I would only have given 3 stars. So come on Decathlon start selling spare parts & offer a service to your customers.