greatever snorkel mask foldable panoramic view full face snorkeling mask with detachable camera mount, dry top set anti-fog&anti-leak, for adults&kids greatever <b>preparation:</b><br>make sure there is no sand on the mask or tube,if there has sand,using water to clear the breathing tube or mask,once the mask is clean then it ready for use.<br><br><b>checking the seal:</b><br>pull the straps of the mask over your head and check the fit of the mask on your face,breath normally to check for any leaks,if you feel slight pressure change when you breath,then you have a good seal,if not,please kindly adjust the mask wire size.<br><br><b>using:</b><br>once in the water,swim on the surface and breathe calmly through your mouth or nose,if you feel light headed remove the mask immediately,keeping your chin slightly up will create the best breathing experience,if you feel any obstruction to your breathing,it may be due to the snorkel being covered in water temporarily,the dry top snorkel design will prevent water from entering through the top of the snorkel,if water leaks into your mask,simply lift your head out of the water and it will drain out of the chin valve,no need emove your mask to clear it of water.<br><br><b>why choose us:</b>the greatever foldable snorkeling mask effectively solves the problems of the non foldable snorkeling mask: the non foldable one is not easy to install,and the breathing tube is easy to fall off when it is used; after several times of use,it is necessary to replace its accessories (o type seal ring).the greatever foldable snorkeling mask is easy to install,and its breathing tube will not fall off.there is no need to replace any accessories,and the mask has a longer service life.