A test tube holder is a laboratory tool used to hold and manipulate test tubes safely and securely. It is used to hold a test tube in place when the tube is hot or should not be touched. The holder consists of a piece of wire bent into a U-shape with loops on each end that can be squeezed together to hold the test tube. The loops may have plastic or rubber coating to provide extra grip and prevent scratching of the test tube. The wire may be straight or have a curved shape, depending on the application. Test tube holders are used to hold test tubes securely while they are being filled, stirred, or heated, and are especially useful when working with multiple tubes at once. They also provide a safe and easy way to transport test tubes from one location to another without risk of dropping or spilling. When heating a test tube with liquid or solid contained inside, the holder ought to tightly hold a test tube in order for the tube to be safely held while heating. The proper distance between the test tube holder and the top of the test tube is approximately 3 centimeters.