The Jabra BT620s headset sports a flexible, though non-adjustable, behind-the-neck design. At either end of the black neckband sit two round, silver earpieces that measure 2.4 inches in diameter. Although the headphones weigh a light 3.5 ounces, they feel heavy when worn. The neckband curves (above the earpieces) can be hooked over the ears to provide a more secure fit, but I found after 10 minutes that the resulting pressure on my ears was quite uncomfortable. Unfortunately, the headset has a tendency to slip off when not supported in this fashion--a serious design flaw, in my opinion. James Kim claims they're moderately comfortable, and they didn't slip off his ears. However, he did get a small headache from the prolonged pressure on his ears. Overall, the BT620s may be OK for those with tough ears, but it's a pain for the rest of us.
The center of each earpiece cover is essentially a large function button: play/pause/power sits on the right side, and answer/end call on the left. The BT620s also has a volume toggle on the right earphone; on the left you'll find a standard mini-USB port, a pinhole microphone, and track shuttle keys that work only for devices (select cell phones and smart phones) that support the Bluetooth remote control profile. Headphone accessories include a standard USB cable, an AC power adapter, a soft pouch, and a quick start guide. You'll certainly want to refer to the guide when first setting up the BT620s.
As of this writing, there are no Bluetooth MP3 players on the market, so you'll need to pick up a separate adapter. Naturally, Jabra tests its headsets with its own adapters, so your best bet is the Jabra A120 ($49, connects via a 3.5mm jack for use with all MP3 players) or the A125 ($59, made for the Apple iPod). These small devices (1.75x1.2x0.5 inches) charge via mini-USB and offer a rated 10-hour battery life. Even better, some users report them working with other stereo Bluetooth headphones, such as the Motorola S805.
You can expect up to 16 hours of talk time or 14 hours of music playback. When the headphones run out of juice, you can charge them via the mini-USB cord. If you go the computer route, you can simultaneously listen to music on your PC while charging at a reduced rate--a useful, if extraneous, feature. You can also pair the wireless headset with your PC, but in most cases, audio will be in mono and the quality will be poor.
We tested the Jabra BT620s with an MP3 player (Creative Zen V Plus) for music sound quality and a smart phone (Cingular 8525) for audio-call quality. When we used the A120 transmitter, we got excellent range, wandering well over 50 feet from the source before the sound cut out. Music sounded rich and detailed overall, but suffered from an audible background hiss. Call quality fared worse, with both ends of the conversation complaining about tinny, echoing audio.