Get ready for the most amazing snorkeling experience with this ANSUN full face mask! The 180° panoramic view lets you see everything underwater without the limited vision of traditional masks. The advanced breathing system features a double float design with separate intake and exhaust channels - this means smoother breathing without CO2 buildup. The anti-fog technology uses double concave and convex waterproof grooves and an enlarged silicone skirt to prevent exhaust from fogging your view. The dry top system automatically seals when submerged, preventing water from entering through the top. Made from high-quality PC and food-grade silicone that's soft against your skin and won't cause allergies. The chin valve lets water drain out easily without removing the mask. For sizing, measure from your nose bridge to chin bottom - S/M fits measurements ≤4.72\ (12cm), L/XL fits >4.72\. Important safety notes: this is for surface snorkeling only, not freediving. Swim calmly on the surface, keep your chin slightly raised, and take regular breaks. If you feel lightheaded, remove the mask immediately. The mask is easily removable for compact travel storage. ANSUN stands behind their product with an exceptional satisfaction guarantee. Whether you're a beginner or experienced snorkeler, this mask makes exploring underwater worlds more comfortable and enjoyable than ever before!