Since police moved from radar to laser (difference explained here http://www.dtmpower.net/forum/genera...ser-radar.html) its been getting harder to get out of tickets. However, for some reason states havent made jammers illegal. There's a few ways they work, either when the laser hits you, the jammer sends back to the police's machine that youre going say 50, when really you're going 75. Or, like the Interceptor (Laser Interceptor - The Ultimate Laser Jammer - Product Info.) works, is it completely blocks out the signal, so the police's machine reads "- -" (no speed)

The interceptor is the top one on the market atm.