As of July 1, California will join more than two dozen other states as the “hands-free law” goes into effect.

It will be illegal to hold a cell phone to our ears while driving, which means that we’ll have to rely on hands-free device such as a headset or speaker kit.

Our gadget guru Phil Baker test-traveled some of the top items on the market and reports his findings …

SPEAKER KIT

A speaker kit is a small box with a microphone and speaker that mounts on your visor and connects to your phone via Bluetooth. It has a built-in rechargeable battery that lasts for a week or two. Controls let you answer and hang up, and there’s noise reduction circuitry to reduce background noise so you don’t sound as if you’re in a tunnel. They need recharging less often than a headset and are the only choice for those that don’t like putting something in their ear.

BlueAnt Supertooth Light Bluetooth Handsfree ($75)
This is a slick-looking design in glossy black with large controls and a strong speaker. It attaches to your visor using a magnetic clip. Sound is quite good and it does a decent job of reducing background noise, but no speaker kit is as good as the best headset. It comes with an AC charger, but an auto charger would be more useful. A more expensive ($130) version, Supertooth 3, lets you upload your phone’s address book and call by name. Both work well and are recommended. www.myblueant.com

Anycom SCK-1 Solar Bluetooth Car Kit ($60)
This has what, at first glance, seems to be a valuable feature–built-in solar cells to power the device. But it provided little value, requiring the built-in battery to provide most of the power, and it needs to be mounted on your windshield to be exposed to sunlight. My conversations came across less clearly than the others. Not recommended. www.anycom.com

Parrot Bluetooth Portable Speaker Minikit ($70)
This unit is slightly smaller than the BlueAnt but with a more retro design. Its performance is comparable to the BlueAnt and it comes with both an AC and car charger. Recommended. www.driveblue.com

BLUETOOTH HEADSETS

Many prefer headsets because they’re portable and can be used anywhere you happen to be. I tested the New Jawbone ($129 - at right), the BlueAnt Z9i ($129), and the Plantronics 925 ($149), all recently announced models. Prices shown are list; most are too new to be widely discounted yet.

All fit into the ear using a rubber tip, and all but the Plantronics has an optional-use ear loop to add some stability.

Talk time is similar for all but the Plantronics, which has an extra battery built into its case to double its runtime. Most get through one day of moderate use before needing to be recharged.

I tested each unit talking with a friend and determining the clarity of the conversation at his end with no noise in the background, with the radio playing in the background, and then the air conditioner running on high.

THE RESULTS

With no noise in the background, all were clear on both ends of the conversation with minimal differences between units.

But with the radio playing at a moderately loud level and the air condition blowing, it was hard for me to hear myself talking.

The New Jawbone worked the best so that the radio was barely audible and my words came through loud and clear. The Jawbone needed to be up against the face to detect my jaw moving.

The Plantronics 925 and BlueAnt Z9i worked well, but were not quite as successful in reducing background noise. I could be heard, but not as clearly as on the Jawbone with the radio playing loudly.

Other considerations are appearance, fit and ease of use. The Jawbone and Plantronics models come in gold and silver and are the most stylish for both men and women.

While fit varies among individuals, I found the Plantronics to be the most comfortable. All come with a charger and cables to charge from your computer’s USB port.

Where do you put the headset when you’re not using it? Plantronics provides a battery case and the BlueAnt has a built-in pocket clip. Jawbone does not come with a case.

Bluetooth technology is far from perfect so expect situations where even the best models don’t work in all situations. But as a group these three models work better than the previous generation of products.

If you want something less expensive consider a wired headset such as the Plantronics MX250 ($20) or a similar product with a boom that brings the microphone as close as possible to your mouth. Or if you don’t mind the weight, last year’s Jawbone ($80) works nearly as well as the new model.

By Phil Baker. Originally published in the San Diego Transcript. Read Phil’s blog http://blog.philipgbaker.com.

Get in-depth reports on three options, including the BlueAnt and Jawbone in Greenberg-Tested Wireless Bluetooth Headsets.

Get more information on helpful Travel Gadgets.

Previously by Phil Baker:

Battle of the Gadgets: the Smartphone Wars

Gadgets for Business Travelers on the Go

Don’t Leave Home Without ‘Em: Top Travel Gadgets

Thin Is In: Mac Air Vs. PC Thinkpad