What feature of a clamp ensures it attaches securely to a truss or pipe?

A locking mechanism is essential for ensuring that a clamp securely attaches to a truss or pipe. This feature prevents any unintended movement or disengagement during use, which is crucial in rigging applications where safety is paramount. The locking mechanism typically works by providing a means to tighten the clamp around the truss or pipe, ensuring a secure fit that can withstand the rigors of weight loads and dynamic movements that are common in theatrical rigging.

While rubber grips, movable joints, and adjustable screws play important roles in the function of clamps, they do not primarily provide the same level of security against movement. Rubber grips may enhance friction and provide a better hold, but they do not inherently lock the connection. Movable joints might allow for better positioning, but they can introduce flexibility that could compromise stability. Adjustable screws can help tailor the fit but don't lock the clamp in place by themselves. The locking mechanism therefore stands out as the most critical feature for a secure attachment.