When moving cylinders, what must always be securely in place?

The valve protection cap is crucial when moving cylinders because it provides essential protection to the valve from physical damage during transportation. The valve is a critical part of the cylinder, controlling the release of the contents, whether gas or liquid, and if it were to be damaged, it could lead to serious safety hazards, including leaks or unintended releases of pressurized contents. By ensuring the valve protection cap is securely in place, it helps to prevent any possible accidents while moving the cylinder, ensuring safe handling practices.

The other options—hose clamps, valves, and regulators—while important for various functions in gas management processes, do not specifically offer the same level of physical protection to the cylinder's valve itself during transit. The hose clamps are used to secure hoses, valves control the flow, and regulators manage pressure but none of these items provide the protective barrier that the valve protection cap offers to protect the cylinder's valve from being damaged or compromised during movement.