This is an additive that acts as an emulsifier for water in gasoline. In addition it improves many other useful performances in engines as stated below, I highlighted the section that speaks about water.

GSL-4
A highly concentrated ash less, non-phosphorous fuel supplement for gasoline that improves many areas of performance while reducing emissions.
Improves Performance of Gasoline

GSL-4 contains compounds and ingredients that improve performance aspects of gasoline as it is available today. Gasoline sold in the United States and other developed countries are a highly consistent product designed to be used shortly after leaving the refinery. However, when left in fuel tanks and fuel systems, problems occur with even the best of this fuel. This often becomes a problem in both marine and agricultural applications. Leaded gasoline is often no longer available in many localities because of environmental concerns and the use of catalytic converts. Many older engines require leaded gasoline to reduce wear damage to vital engine parts. Oxygenated gasoline is often required in urban areas. This also creates combustion problems that can diminish engine performance.

Cleans Fuel Lines, Carburetors and Injectors
GSL-4 contain a complete yet gentle detergent that cleans and dissolves mileage-robbing gum, varnish, and carbon in fuel lines, carburetors, injectors and combustion chambers. It inhibits buildup of new deposits and keeps moving parts in carburetors working freely.

Water Control Agent
GSL-4 contains a surfactant that breaks down the surface tension of water. This chemical emulsifier breaks water into microscopic particles and disperses them into the fuel to be burned during the combustion cycle. It removes water from fuel tanks, gas lines, and bulk storage tanks. Gas line freeze-up is eliminated when the system is rid of water. Rust and corrosion of fuel tanks and fuel system components is greatly reduced.

Emission Reduction
GSL-4 contains an ash less organic combustion improver that changes the molecular structure of the gasoline to let it burn more completely, yet leaves no harmful deposits. Complete combustion means less unburned particles will be emitted through the tail pipe. Unburned hydrocarbons are an essential component of photosynthesis smog.

Lead Substitute
GSL-4 contains a compound designed to reduce wear damage to vital engine parts caused by unleaded gasoline. The lead-replacing lubricant accomplishes the same function as lead in regular gasoline, preventing metal-to-metal contact between valves and valve seats. It helps piston rings and valve stems work freely, resulting in smoother operation, reduced wear and extended engine life. The compound assures that parts in contact with the fuel, particularly the carburetor, will work freely. GSL-4 is recommended for increasing the life span of older agricultural, commercial, and marine engines that require leaded fuel.

Improved Mileage and Power
GSL-4 includes a combustion modifier that provides a smoother power stroke of the piston. It contributes to more complete combustion so the engine will get every available bit of energy out of the fuel. The result is better gasoline mileage and more power. Results from your vehicle will depend on the quality of the fuel burned and the condition of the engine.