... Eco-friendly ,Toxic Free Dry/Wet (Semi-wet) Design High Quality Dry Snorkel In China, Diving Gear ,Snorkelling 100% Silicone Mouthpiece,PVC Tube ... silica gel slot .amateur divers have to keep breathing rate in control first , breathing should be kept regularly no matter how ... cause dangerous situation. Take Maldives depth snorkeling for example , diving in the center of the sea by boat ,the depth of ...