Boosters are one of the most critical areas of a carburetor in terms of performance. Everything done to tune an engine is dependent on the correct booster and how well it is matched to the application. Annular boosters are found on every style of carburetor we make, and proper research should be done to determine your specific needs. Annular boosters employ several small holes to discharge the air/fuel mixture into the venturi, whereas all other types of boosters (i.e downleg, straight) use one hole. Think of the difference between the boosters the same as the difference between a water hose and a shower head. Annular boosters provide better fuel atomiztion and can increase power and torque, depending on your application. The emphasis here is that not all applications will see a benefit from an annular booster.