The 15/15mm carburetor from Bing is visually identical to the original 12/12mm Bing carburetor, but offers better cylinder filling and improved internal cooling. This significantly contributes to the engine's lifespan. Additionally, the power delivery is much fuller, and even at high RPMs, the mixture does not lean out as much. The original air filter can be reused, and the system works even better with the power filter. Nozzles Bing diameter 3.5mm fit.