The Mainnav MG-600 is a useful navigation gadget for serious cyclists. The gadget can keep track of speed, distance, time, odometer, GPS coordinates and elevation. The cool factor for the Mainnav MG-600 is that it can also act as a GPS data logger and has an embedded light sensor. You can then view the logged data on Google Earth and Google Maps. The Mainnav MG-600 comes equipped with a rechargeable lithium-ion (850mAh) battery that will last for up to 18-hours on a single charge. [Navigadget]