It looks like a small radar detector, and all you do is put it in the middle of your car on the windshield. Then you have too level it off according to the numbers on the screen. And then put it in the 1/4 mile mode and when it says go you go. It uses the motion of your car, and sensors to get the readings. I neverused it at the track just on the street. A friend of mine used it and it was within a tenth. It a really cool if you ask me.
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98Cobra
off road x-pipe, flowmasters, 3.73 rear end(4.30's soon),Mac Cold Air,Ripper Shifter, Nitto Drag Radials