Yep.

The "you can buy them" jammers - radar and laser - are worthless.

However, it is not difficult at all to build a jammer that absolutely WILL work. The laser ones are legal to build and use. Radar ones are ILLEGAL (as in Federal Offense, go straight to jail) and the cop WILL know you have one when he points his fancy gun at you and it comes back with all dashes.

(BTW, he'll also know you have one for laser for the same reason, but in that case there's nothing he can do about it, other than pull you over and claim he smells dope, then call the K9 unit and make you wait for an hour until it gets there, plus do a VERY thorough search. Hope your "best friend" didn't leave a seed in your ashtray a few years back..... if you know what I mean!)

A Valentine One, properly used, will save you nearly all of the time. "Properly used" does not including doing 90 in a 30 mph zone when you're the only car on the road......