5 Forerunner ® 205/305 Owner’s ManualappendIxReplacing the Heart RateMonitor BatteryThe heart rate monitor containsa user replaceable CR2032battery. Be sure to dispose of oldbatteries properly. To replace thebattery, locate the circular batterycover on the back of the heartrate monitor. Use a coin to twistthe cover counter-clockwise untilit is loose enough to remove.Remove the cover and replacethe battery. Be careful not todamage or lose the o-ring gasketon the cover. Then use a coin totwist the cover back into place.Data FieldsThe data fields available on anyTimer page change based onthe accessories you own and thespeed units you have selectedfor a sport. Starred (*) data fieldsare available with the Forerunner305 only.Cadence*—revolutions of thecrank arm per minute.Cadence – Avg*—averagecadence for the duration of yourcurrent ride.Cadence – Lap*—averagecadence for current lap.Calories—amount of caloriesburned.Date—current day, month, andyear.Distance—distance traveled oncurrent run.