Has anyone used one of these http://www.goodluckbuy.com/fpv-f ... l?&currency=gbp

if so could you post a Video clip.

What does this do?

jamesnns@gmail. Posted at 2014-12-21 01:17
What does this do?

In theory it would display certain data (voltage, GPS, etc.) on your screen...

OSD stands for "On screen data".

But this is a 3rd party item and you wouldn't see me unplugging my GPS, etc. and then trusting this board to have all the data run through it!  Also, it very well may not work with the DJI apps - they are showing it with it's own camera and FPV monitor.