I have one wired in....works fine as long as the racing venue has the system activated. Since I do not have a full data system in the car, this is a cheap way to check lap times...learning from my mistake, make sure and mount it high enough to be able to view it easily. Mine is too low. At least with these, you don't have to go mount a beacon somewhere...
Agree with both comments from bill and bob. I have one without the full tilt data setup and works great at most of the tracks. Bob outlined pretty much every feature I use it for...