An Under counter RO Water Purifier That Intelligently Retains Essential Minerals. When you are unsure about the impurities in your drinking water and food, there is Kent Sterling Plus 6L RO + UV + UF Water Purifier to take care of your health. It’s Mineral RO technology retains essential natural minerals in the purified water. It has fully automatic operation which allows the purifier to begin the purification process. It has a fully automatic operation which shuts off when the storage tank is full and starts the purification process when the water in storage tank falls below the maximum level. The compact water purifier is ideal for under-the-counter installation.