I was browsing YouTube and cam across a video 'testing' them. The video looks into if they work and what gains you might get.
[ame]http://youtu.be/gCi2yo4UqPI[/ame]
There's the link have a watch and see, but it does make you wonder if some product make any difference...
[ame]http://youtu.be/gCi2yo4UqPI[/ame]
There's the link have a watch and see, but it does make you wonder if some product make any difference...