Features: Pressure relief valves at the top: Press it with moderate force to release the pressure easily, bite it after entering the water, and press it once when you are to inhale to release the pressure and drain the water. Pressure gauge: With luminous function, it is still clear at 80 meters underwater. The stainless steel material is waterproof, corrosion-resistant, high hardness, compressive and durable. One-way inflatable filter: high-density filter; prevent impurities and dust from entering the air-intake channel, and cover the dust-proof cover for double safety after inflation, which is more assured. The food-grade breathing mouthpiece is made of food-grade silicone material, which is safe, and ergonomically designed. It is easy to bite and breathing freely. When connecting with the breathing valves, be sure to tighten it to prevent air-leakage. Breathing oxygen cylinders: aviation aluminum is used, and the surfaces adopts plastic spraying technology to store high-pressure-gas, which is durable and resistant to seawater corrosion. Notice: 1.Actual color may be slightly different from the image due to different light effect 2.Please allow 1-3cm deviation due to manual measurement Material: Aluminum 6061-T6 Capacity: 0.5L Package List: 2 x breathing valves 2 x 0.5L oxygen cylinders 1 x Adapter 2 x Diving Bags 1 x Tote bag 2 x anti-lost rope 2 x Black Diving Goggles