A rear fog light is a bright red light mounted at the back of a vehicle, designed to enhance fog light visibility in challenging weather conditions like heavy fog, rain, snow, or dust storms. Unlike standard taillights, a rear fog light is significantly brighter, helping to prevent rear-end collisions by making your vehicle more noticeable to drivers behind you in poor visibility conditions.
- Main Purpose: The fog rear light ensures your car is more visible to other drivers, improving safety during adverse weather. 
- Legal Requirement: In Europe, rear fog lights are mandatory under ECE R38 regulations, and many other regions also require their use to ensure road safety.