Bests & Worsts Reviews from Amazon

I only wish it were possible to give this device a negative star rating. Being an inquisitive electronics engineer, I disassembled one of these. It comprises a pretty plastic case, a few diodes, resistors and capacitors - none of which can have -any- effect on any vehicle's fuel economy or performance. The only thing it improves is the manufacturer's profit. Any claims to the contrary are written either by the sellers of this automotive "snake oil", or their victims, who unconsciously change their driving styles when the device is plugged in.