they work ok. the only problem is that they're IR instead of thermocouple probe. they don't give very accurate internal temps, just surface temps. that means that they're not good at telling you how hot your tires actually run. they ARE good, however, at telling you how your temps compare at the inside, center and outside of the tread, so they can be used to evaluate camber and pressure fairly accurately. i use one i picked up from harbor freight for $28. works fine.