Which item is essential for a lifeguard when performing a rescue?

The rescue tube is an essential item for a lifeguard when performing a rescue because it provides a flotation aid that can help both the rescuer and the individual in distress. The design of the rescue tube allows the lifeguard to reach out to a struggling swimmer while maintaining their own stability and buoyancy in the water. Additionally, the rescue tube can be used to support the person being rescued, reducing the risk of further danger during the rescue process.

This equipment is specifically designed for such situations, making it a fundamental tool in a lifeguard's arsenal. It enables a more effective and safer rescue, allowing lifeguards to quickly assist individuals in distress without putting themselves at unnecessary risk. Other items, while useful, do not serve the same critical function in an emergency rescue scenario.