Just as mobile phones are a revolution, I see this portable personal air conditioner on a parallel platform. This handheld gadget runs on 4 AA batteries (not included) providing power for about 5 hours. Just drizzle some water onto a sponge and place it in the device. The fan then draws air over the damp sponge, cooling it by up to 25 degrees Fahrenheit. You can now enjoy cool breezes wherever you go for an AC that costs just $40. In short, it’s a must-have gadget for summer.