A hand-siphon is a device used to transfer liquids from one container to another. It consists of a flexible tube with one end inserted into the container holding the liquid and the other end in the new container. The tube is connected to a pump, which is operated by hand and uses suction to draw the liquid through the tube and into the new container. This can be used for tasks such as transferring fuel from a gas can to a lawn mower, filling a pool with water, or even emptying a fish tank. Hand-siphons are relatively inexpensive and easy to use, making them a useful tool for a variety of tasks.