It has a big water capacity in comparison to other diffusers and it can hold 880ml. Finally, you can spread holistic happiness in your home for multiple hours. The moon night light lamp function runs for multiple hours on inbuilt batteries which you can charge with the included USB charger. No worries, you don't have to use your own batteries. It comes with 3 different lights! A press of a button and this stress relief Full Moon comes to life in different colors; warm, soft white and yellow, all naturally soothing for eyes. Note: Due to the "light" nature of purified water, water will accumulate on the surface of the body, causing water to enter the charging port. It is recommended to use "tap water" for humidification At the beginning of use, please pull out the sponge rod first, and then put it back to the original position after the sponge absorbs all the water!! The product has no waterproof function. It is strictly prohibited to rollover the product during use, otherwise it will cause water ingress into the motherboard and damage the product