Garrett ATX is waterproof up to 10 feet for gold and jewelry detection. Garrett Sea Hunter MK-II operates up to 200 feet underwater. Whites TDI Beach Hunter reaches depths up to 25 feet. Tesoro Sand Shark can detect targets up to 200 feet deep. KKmoon Metal Detector is cheapest option with waterproof body
Rebreather needed for underwater breathing. Rope gun required for ziplines. Both items must be found before entering cave