Replacement BELL Pro Star / Race Star / SRT Photochromic. Protint™ Photochromic Shield: Now with a Bell ProTint shield. Activated by ultraviolet light, ProTint shields adapt to changing light conditions, providing enhanced vision during any ride. Offering exceptional clarity in low-light conditions, ProTint shields quickly darken when exposed to intense sunlight. This adaptive technology helps your eyes adapt to conditions, even when they change as fast as the road. It enhances your ride.