Which helmet feature is particularly important in preventing sunburn?

The visor is an essential feature for preventing sunburn because it extends beyond the front of the helmet, providing shade to the face and eyes. This shading effect helps protect the skin from direct exposure to the sun's harmful ultraviolet (UV) rays, which can lead to sunburn. By blocking some of the sunlight, a visor reduces the likelihood of skin damage and discomfort that can arise from prolonged sun exposure, particularly when riding or participating in outdoor activities where the head is frequently exposed to direct sunlight.

The other features, while beneficial in different ways, do not specifically address sunburn prevention. For instance, lightweight material enhances comfort and reduces fatigue, bright colors can aid in visibility and safety in low-light situations, and adjustable straps ensure a proper fit for stability and security. However, none of these features provide the direct shade and protection from UV rays that a visor offers.