Garmin Edge 305 Waterproof Cycling GPS with Speed/Cadence. Offering a cycling computer, GPS and Cadence Sensor. The Edge 305 incorporates a barometric altimeter for extremely accurate elevation and vertical profile data. Recreational cyclists looking for the perfect touring companion and fitness partner will love the Edge 305. The devices along with the PC based training software has a virtual cyclist that uses your desired speed against which you can measure yourself.