Athletes who already own an RS800 Training system can purchase the G3 GPS Sensor separately as an accessory. Incorporating the SiRFstarIII¿ chipset, the G3 GPS Sensor talks wirelessly to the RS8000 providing excellent coverage and optimal power consumption. With the G3 GPS (global positioning system) Sensor added to the RS800 , what becomes , is a multisport training system that enables athletes to measure speed and distance for a variety of outdoor sports including running, cycling, kayaking, hiking, canyoneering, in-line skating, cross-country and downhill skiing.