In all, the Energy Shot is compatible for use with most USB devices and uses 4 x AA batteries for Instant Power!!
Other chargers in the market use two AA batteries that generate 3V of power. As USB devices require 5V, these other chargers have to elevate the voltage and also have to draw full required current from same two batteries. This dual action leads to faster drainage of the batteries. Compared to this, Energy Shot utilizes four AA batteries and supplies required power to USB devices using circuit, which regulates voltage and thus load is distributed through all four batteries. This gives a longer life time of battery usage, while maintaining correct and safe operation.