I have limited bar space on my commuter and have more stuff than I have space to put it so I needed an option. I liked the simplicity of this option over the Purely Custom accessory mount, even though it puts an item in essentially the same place. The construction sold me.

I bought one, intending to put my Garmin Oregon 450 GPS on it when I wanted to track a road ride.

It didn't work. The mount for the Oregon 450 is too wide for the Paul mount. I had to rework my plan and so I put the light on it instead, and it fits perfectly.

<a href="http://www.flickr.com/photos/8007861@N04/7322511568/" title="Paul Components Stem Cap Light Mount by mtbikernate, on Flickr"><img src="http://farm9.staticflickr.com/8144/7322511568_c702ea5905.jpg" width="333" height="500" alt="Paul Components Stem Cap Light Mount"></a>

More pictures and description of the details on my site.

Paul Components Stem Cap Light Mount Review | The GPS Geek

It would probably still work fine for a smaller GPS like the Edge models which use a different mount. But since all the handhelds seem to use the same mount now, I don't think any of them would work with this stem cap mount.