Final answer:
The device used to link multiple gas cylinders together is called a manifold. It centralizes gas flow control and is essential for maintaining consistent gas pressure and flow from multiple cylinders.
Step-by-step explanation:
The device that utilizes multiple connections to link gas cylinders together is known as a manifold. A manifold allows for the centralization of gas flow control and is often used when consistent gas pressure and flow rate are needed from multiple cylinders. This is particularly important in industrial applications where gases are supplied to processes from a group of cylinders. By using a manifold, cylinders can be changed without interrupting the supply of gas to the process, thereby enhancing safety and efficiency.