The rotary joint in a shower head allows for easy adjustment of the angle, providing a customizable shower experience. This feature ensures that you can position the shower head to your desired angle, allowing for a more comfortable and enjoyable shower. Additionally, the injected air technology used in the shower head helps to conserve water. By mixing air with the water flow, the shower head creates a powerful rain shower effect while using less water. This not only helps to save water but also ensures a consistent and powerful shower experience, even when the water pressure is low.