Specifications1. Shell material: high transparency and corrosion resistant Germany Bayer 2805 PC 2. Waterproof depth: 40 meters 3. Lens material: Optical imaging tempered glass, AF AR double-layer optical coating 4. Button material: Aluminum alloy 6063 5. Spring material: 304 stainless steel 6. Waterproof ring material: Amorphous high activity silica gel 7. Main body and back cover connecting shaft material: 304 stainless steel, high hardness and corrosion resistance 8. Application: Skiing, surfing, diving, swimming, selfie, swimming, climbing, skydiving