WaterFirst Dr.water has undergone professional NSF, SGS, and EPA certifications to ensure absolute purity and safety of water quality. Note: When water tank is lacking, please lift the water tank and pour out the waste water, and refill tap water the entire water tank to MAX WATER LEVEL LINE 2 In 1 Purification & 3S Instant Heat: By reverse osmosis filter, effective remove 99.99% of over 1,000 harmful contaminants in the tap water, including chlorine, TDS (fluoride, nitrates/nitrites), radon, arsenic, radium, and nuclear radiation) and etc. WaterFirst RO water system combined with a 5-Stages 0.0001 m RO filter can take water purification to another level. You deserve to taste it. With 3S instant heat NEW technology, you also can enjoy a delicious cup of hot drinking in a short time 4 Temp Setting and 6 Water Volume Options: WaterFirst offers a variety of options with 4 temperature including room temperature, 113 F(Milk), 185 F(Tea), and 203 F(Coffee), along with 6 water volume: 6 oz, 8 oz, 10 oz, 12 oz, 14 oz, and continuous dispensing. Simply tap the screen to select your desired temperature and water volume, perfectly meeting the water needs of your home or office Plumber Free, No Installation Required: This portable reverse osmosis water filter is not complex pipeline modifications are needed, avoid expensive kitchen modifications, sit beautifully on your countertop, and it doesn't take up too much space.