Safe Material: This BPA free drinking water dispenser is made of food grade silicone hose, 304 stainless steel and high density ABS plastic, non-toxic, odorless. Easy to Use: Connect the silicone hose to the bottom of the fuselage, put the water hose into the water and put the pump on the barrel neck, you just need to press the switch button and fill the glass or bottle, press again to stop working. USB Battery: This automatic water pump is equipped with a 1200mAh rechargeable lithium battery, it can last 30-40 days or about 4-6 5-gallon water bottles, you can take it to camping or picnic. High Compatibility: Fits barrels with 2.16 inch (5.5 cm) neck without lifting the lid. For 3, 4, 5 liter/can water bottles. Not for threaded/screw caps. Please confirm the barrel neck or contact us before purchasing. Quantitative design: two on/off buttons, one for normal use and one for the 600ml button. Press the 600ml button and the water outlet will automatically shut off once it reaches 600ml.