The sleek Plantronics Discovery 655 is much smaller and easier to pocket than our current Editors' Choice, the Plantronics Voyager 510, but it still sounds great and is quite comfortable to wear. In addition, the 655 has some interesting secondary features, such as a vibrate mode to let you know you're receiving a call, and a separate sleeve for charging the unit with an double-A battery. That can be a true lifesaver if you find yourself out of juice and away from an AC socket. The headset's regular charging sleeve makes a great carrying case and also includes a vibrate feature.

Unlike the 510, which is rather large but very comfortable, you're barely aware that the 655 is fitted to your ear. Since it lacks the 510's curved shape and vise-like grip, the 655 moves around a bit more easily, though there's an attachable plastic ear hook in the box to alleviate this problem. The Plantronics 655 never fell out of my ear during testing (even without the hook attached), something the tiny Samsung WEP200 is prone to do. The 655 did feel a little loose at times, particularly when walking up and down staircases.

The 655 has two rubberized volume-control buttons, and the main call-control key also serves as the unit's power switch. As a result, it's much easier to turn the 655 on than it is the 510, which has a separate, tiny, sharp-edged power button. Linking the Plantronics 655 to your cell phone is also a simple affair: With the 655 turned off, press and hold the power button for 10 seconds, turn on your phone's Discoverable mode, and enter in the usual Plantronics passkey of 0000. We had no problems connecting the 655 to a Cingular 2125, a T-Mobile MDA, a Palm Treo 700p, and a Samsung MM-A920.

Sound quality was generally clear, with good treble balance. It's not as loud as the Voyager 510, but the headset still has plenty of volume. In fact, the 655 actually sounded better than the 510, though its brighter sound and mic tended to pick up more of a room's echo along with a person's voice.

Hearing calls over the headset while walking with moderate wind blowing was no problem, though voice quality degraded with more obtrusive background noise. The 655 includes upgraded DSP compared with the prior model 645, but apparently it still can't work miracles. I tested the 655 while driving with the windows down as well as under an elevated subway, and in both cases the other party had a difficult time making out what I was saying. Leaving the handset on a table, I was able to walk 12 feet away before noticing clicks and pops in the audio, which is a decent but not spectacular range. Battery life fell short of the mark too; the 655 lasted just 3 hours 16 minutes on our battery-rundown test. With regular use, you'll need to charge it almost every night.

With its mediocre endurance and slightly loose fit, the 655 remains just shy of an Editors' Choice award; the Plantronics Voyager 510 is still our favorite Bluetooth headset. But if you think the 510 is too big, definitely check out the 655 for its style, unobtrusiveness, and nice sound.