The Liqui Moly Maintenance Service Kit - 137004 is a comprehensive kit designed for maintaining and servicing a car. It includes various essential products that are necessary for keeping a car in good condition and ensuring its optimal performance. The kit consists of the following contents:

1. Engine Oil - This is a type of oil specifically designed for lubricating and protecting the engine of a car. It helps to reduce friction and wear, and also keeps the engine clean.

2. Fuel System Cleaner - This is a product that helps to clean and maintain the fuel system of a car. It removes deposits and impurities from the fuel lines and injectors, improving fuel efficiency and engine performance.

3. Engine Flush - This is a cleaning agent that is used to remove sludge, dirt, and other contaminants from the engine. It helps to improve the overall performance of the engine and prolong its lifespan.

4. Air Filter Cleaner - This is a product that is used to clean the air filter of a car. It removes dust, dirt, and other particles that can clog the filter and affect the air intake, leading to decreased engine performance.

5. Fuel Stabilizer - This is a product that helps to keep the fuel in the car's tank fresh and prevent it from deteriorating. It also prevents the formation of deposits and corrosion in the fuel system.

Overall, the Liqui Moly Maintenance Service Kit - 137004 is a complete package that provides all the necessary products for maintaining and servicing a car's engine and fuel system. It is a convenient and cost-effective solution for keeping a car in top condition.