Capacity: 0.72 gallon Large opening at the bottom of the water tank: convenient for you to clean the water tank Capacity: 0.72 gallon Large opening at the bottom of the water tank: convenient for you to clean the water tank Run Time: Up to 30 hours.(Run time is calculated based on using cool water and setting the mist level to the low setting. Based on the natural humidity level in your home, the temperature of water you use, and the mist level setting you choose, you may experience longer or shorter run times.) Run Time: Up to 30 hours.(Run time is calculated based on using cool water and setting the mist level to the low setting. Based on the natural humidity level in your home, the temperature of water you use, and the mist level setting you choose, you may experience longer or shorter run times.) Auto Shut-Off Protection: When the tank is empty the unit will shut off automatically. Auto Shut-Off Protection: When the tank is empty the unit will shut off automatically.