That's because it was posted in the Member's area. In the public interest though, I'll go ahead and paste in the contents of the post here: A common question...
Specifics are important... rather than re-type the same info again, I'll re-use one of my old posts:
Note that the quality control on the Cobra units has been an issue sometimes though, with one or both sometimes not working out of the package. Warranty returns are obviously key in this case. If you get a working pair though, they are very good.