Which product mentions improvement of visibility?

The product that mentions improvement of visibility is Rain-X. Rain-X is specifically designed to enhance visibility during inclement weather conditions. It works by creating a hydrophobic surface on the windshield that causes water to bead up and slide off, thereby improving the driver's line of sight when it rains. This characteristic makes it particularly beneficial for maintaining clear visibility, which is crucial for safe driving.

Other products like Tire Dressing and Sonic Gloss have entirely different purposes. Tire Dressing is aimed at enhancing the appearance of tires, providing a shiny finish and protection against cracking. Sonic Gloss serves to maintain and enhance the shine of a vehicle's paint but does not have any direct impact on visibility. Therefore, Rain-X stands out as the correct answer due to its specific formulation aimed at improving visibility while driving in wet conditions.