Been running the GSC10 with a Garmin 800 for 4 years. Had to replace the battery once. Works like a charm, no problems. This is on a tandem. Signal is received fine in both the stoker and captain's positions. I have the 800 set for automatic tire size, so it uses GPS data to calculate tire circumference. That works great, too. I'm always right on the distance when I follow courses or cue sheets. Of course you have to pair the sensor with the Garmin head unit, but that is explained in the instructions which come with the sensor and is easy to do.