I bought this so I could use my PowerTap with the TrainerRoad software.
Installed and working without issue, allowing me live power data synced to Sufferfest films, brilliant!
However note that the Garmin ANT+Agent software does not communicate with the PowerTap, (why would it), its the trainerRoad software that does! Do not plug in the USB stick and expect it to pair with an Edge or a PowerTap, or infact anything that isn't a Forerunner.
The USB ANT chip arrived for me not the larger USB stick as shown in the picture. I have to say the tiny 'chip' is fantastic. It's so small I can leave it in my laptop all the time without noticing it and it's been syncing really well with my forerunner 910xt.
I bought the Garmin USB ANT stick to complement the Garmin FR60 so that I could upload my training data into the Garmin connect website. It does the job beautifully. You need to download a small software from Garmin and the step by step guide is very easy to follow. It can somehow automatically tell when my FR 60 is in range and if it requires syncing with the data on the website thereby being completely hassle free. I can only suspect that it is active at all times it is connected to a USB port. I understand the USB stick also works with the Tanita wireless scales which is a further bonus if I decide to buy one in the future. The only downside is the price (I have seen it on sale @ almost half the price from a well known auction site). If you have any of the compatible Garmin heart rate monitors, this is a well worth it purchase.