Pump Works only when the target container is lower than the source container. When liquid comes close you can pinch the hose and remove the hand pump placing hose end in target container. Hand pump for gasoline, oil, air, water and other common liquids, ideal for emergency gas transfer. Never start the siphon process with your mouth, it's extremely dangerous and grossly inefficient. Not suitable for drink water, salt water and any chemical & corroding liquids. The source fluid should be higher 11 inch or more than the target one (The greater the height difference, the better the effect). Connect the hose to both ends of the rubber pump. The black arrow on the rubber pump point to the flow direction. Put the input side of the hose in the source fluid. Use the hose clips to secure the hose, make it won’t flop out or leak fluid. Squeeze the hand pump 3 or 4 times. When the liquid comes close to the rubber pump, place the outlet hose in the target container. When the fluid level is too low at the bottom of the source container, the pressure will not enough to keep fluid flowing naturally, then need to keep squeezing the rubber pump to finish the pumping job.