Do yourself a favor: make sure your car is up to code by this July—no broken headlamps or taillights, up-to-date registration, etc. – and, oh yeah, make sure you pick up a hands-free Bluetooth device for your cell phone.

On July 1st a new law will go into effect in California making it illegal to talk on a wireless phone while operating a motor vehicle. If you are 18 or older, and you want to use your phone while driving, you will need to use a hands-free device – no “ifs”, “ands”, or “buts” about it—and there will be no grace period either. If you are under 18, you can’t use your phone while driving, period. The fines are small ($20 first offense, and $50 thereafter—but amounts can triple with penalty assessments) but convictions will appear on your driving record, potentially ballooning insurance fees. Find out all about the law here: http://www.dmv.ca.gov/cellularphonelaws/index.htm.

Contrary to the rumor mill you can and will be pulled over just for using your phone—no other infractions are needed. (However, running around with a headlight out and gabbing with your wireless glued to your ear will only increase your odds of getting nailed.) With the hassles and fees that come with ignoring the law, and the relatively low cost of Bluetooth hands-free devices these days, it just makes sense to cover your ass—dontcha think?

We put 12 of the newest Bluetooth devices through the wringer to help you find the right one for your car-talking habits. All of the devices were tested with one phone along the same stretch of highway at the same time of day, and call clarity was compared via voicemail recordings. Read on to find out which ones made the grade. (Prices listed are MSRP—street prices may be much lower.)

BlueAnt Z9

Website: www.myblueant.com
Battery: 5.5 hours talk time, 200 hours standby
Price (MSRP): $79.99

One of the smallest and least expensive devices in our roundup, the Z9 sports two levels of noise reduction, which BlueAnt terms Voice Isolation Technology. The first level is for standard use in normal everyday environments, the second level is for use in “extreme noise” environments, such as a car. We found both levels worked fairly well, though our voice did sound muted at times when using the maximum setting. Also, we did experience some intermittent and random “crackle” interference. Overall the Z9 delivers solid performance while also being both easy and comfortable to use.

Verdict: 7

Jabra SP5050

Website: www.jabra.com
Battery: 6 hours talk time, 150 hours standby
Price (MSRP): $98.78

Okay, so you don’t like sticking anything other than your finger into your ears. No problem—check out the sleek and stylish Jabra SP5050 speakerphone. This device clips onto your sun visor and is remarkable easy to set up and use. There’s even a night driving mode that turns off the LEDs so they won’t distract you. We also like that the device shut off automatically after losing connection with your phone for more than 15 minutes, which saves battery life.

Too bad the included car-charger cord is only three feet long, as it can interfere with driving controls if you have to use the charger while on the road. Also, while the call quality was great on surface streets, there was a definite downgrade when we hit the highway (due to escalated cabin noise) – something we experienced with all the speakerphones we tested.

Verdict: 7

Cardo S-640

Website: www.cardowireless.com
Battery: 8 hours talk time, 250 hours standby
Price (MSRP): $59.99

The S-640 is a sleek, miniscule device that clips to your shirt or pocket and strings along a tethered earbud on an 18-inch cord. In addition to the fashion benefits, this also makes the S-640 very comfortable to use during long drives. Unfortunately, the device lacks noise-cancellation technology, and our voice tended to sound more muffled on calls when compared to standard headsets. Voice clarity during non-highway use—both in the car and out—was excellent, however.

Verdict: 6

Cardo S-800

Website: www.cardowireless.com
Battery: 8 hours talk time, 168 hours standby
Price (MSRP): $79.99

The S-800 is one of the most feature-packed headsets we tested. Just about all the latest buzzwords are here: favorite numbers hot button, call back, location buzzer (love it!), auto answer, missed call indicator, conference call, voice dial—the list goes on. It also looks exceptionally cool it its silver shell (we like shiny things). Plus, embedded audio balancing, noise reduction, and speaker boost combine to deliver voice quality that is among the best we have tested.

Unfortunately, the button layout and overall design make the S-800 difficult to use, and the large earbud made for an uncomfortable fit—which definitely isn’t ideal in the car. An optional ear loop improves fit slightly, and a lanyard is included to wear the device around your neck while not in use.

Verdict: 7