The new POLINI A/F device measures the air/fuel ratio and it is the ideal tool to find the perfect carburetion setting of your 4 stroke motorcycle. The compact dimensions also allow you to leave it positioned on the bike directly connected to the battery and you can easily get the A/F information every time you need. The white backlighting improves vision in the night and it is active when connected to the battery. Polini A/F can also be used by motorcycles without battery as supplied with internal battery. In this case, to save the battery, it is not backlit.