Graduated cylinders are used to measure liquid volumes and are more accurate than flasks or beakers. They are tall, narrow, and cylindrical vessels marked with graduations. Made of glass or plastic, larger graduated cylinders are typically plastic, which is lightweight and less likely to break than glass. Graduated cylinders have a solid base or foot for stability and a spout to aid in pouring. Because they can be somewhat unstable, some glass cylinders feature a plastic bumper or ring to help prevent breakage if tipped over. Mixing graduated cylinders have ground glass joints instead of a spout or are sealed with a stopper. These are commonly used to make dilutions.