The holts redex petrol system cleaner is a simple part of a car maintenance routine which can increase fuel economy improve the working life of your injectors and extend the life of your car its like an exercise which keeps your car fit pour a shot of redex petrol system cleaner into the tank regularly to keep your car driving further during combustion deposits build up on your fuel injectors and lead to an inefficient use of petrol redex stops this build up and cleans the injectors to save you