A more sophisticated fueling system in combination with optimized heat management, eliminates the need for a fan and the associated electronics. So for each shot, the Grex GCP650 only requires a very small amount of energy from the batteries to power the ignition system. The driving force for the design of this tool was to develop the most compact cordless finish nailer, so naturally we wanted to choose a battery that is small. And we also did not want to tie the user to another rechargable battery platform. So the decision was to design the ignition system to run on the most widely available, and low cost batteries available; the AAA.