In our previous reviews of Plantronics Bluetooth headsets such as the Plantronics M2500 and the Plantronics M3500, we noted that we mostly enjoyed the sound quality but weren't terribly impressed with the fit or the tiny controls. On the M3500, the fit was much too tight, while on the M2500, it was too loose. With the new Plantronics Voyager M510, however, we found the fit to be just about right. That's not to say it couldn't be better, but it was an improvement over previous models.

The Plantronics Voyager 510 is available in several different versions, all of which are expensive. The 510 ($99) is simply the headset with a compact charger. The 510S ($299) adds a desktop charger that can be hooked to a landline phone for taking calls on the headset. The 510SL ($379) comes with the desktop charger, as well as a handset lifter that raises your landline phone off the cradle in a manner similar to the GN Netcom GN 6210. Finally, the 510SL Plus ($429) includes all the aforementioned offerings along with a variety of accessories such as a car charger, a USB charger, and a belt-clip carrying pouch. You can buy the lifter alone for $79 or the base by itself for $229.

The headset itself is gray and black and largely resembles the M2500 with its behind-the-ear-fit, swiveling boom mic, and nonprotruding earpiece. Though it's among the largest Bluetooth headsets we've seen, it still weighs a slight 0.67 ounce. Since the battery rests in the wraparound ear hook, it's not wholly flexible, but we were able to get a mostly secure fit on either ear. Be advised, however, that users with smaller ears may find it too loose. Unfortunately, as with its predecessors, controls on the Voyager 510 were tiny and tough to manipulate while wearing. The volume rocker wasn't bad, but the power/muting key located immediately above it was so small that we had trouble finding it even when we were holding the headset in our hand. Likewise, the call control button at the top of the boom mic was also too little for our tastes. The headset has one indicator light that flashes red during charging and blue during a call.

The desktop charging base is furnished in an attractive silver and black color scheme. At 4.75 by 4.25 by 4.0 inches, the Plantronics Voyager 510 is on the bulky side, but the rounded edges make for an attractive look overall, and we prefer it over the GN 6210. Easily accessible, the headset rests in a charging cradle on the front of the base. To make and end a call on either your landline or your cell phone, you can lift the headset out of the cradle, as well as press the call control buttons on the headset or the top of the base. Alternatively, if you're using the handset lifter (see below), the same steps automatically raise your landline phone off the cradle. Other keys on the base consist of a volume control, a power switch for the handset lifter, and buttons for adjusting the frequency so that it matches your landline phone's. Additionally, a red indicator light indicates whether the base is on and a blue light flashes when the headset is in use. On a final note, we found that once the base is connected to the power cord, the landline phone and the headset lifter comprise a somewhat messy setup.

The handset lifter attached easily to our landline phone with adhesive strips. We had to experiment with the position, but once we got it in the correct place, it worked without incident. Plantronics wisely included a switch on the lifter that adjusts the height to which if lifts the phone.

We tested the Plantronics Voyager 510 with a Sony Ericsson S710a. The pairing process was easy to understand, and we were up and running in no time. Sound quality for cell phone calls was mostly good, though with a somewhat hollow quality at times. Callers asked if we were using a headset, but that's nothing out of the ordinary. Previous Plantronics headsets picked up a noticeable amount of wind noise, but the 510 came with a windscreen ear tip and mic cover that provided some improvement. The headset came with a fair amount of features, including noise canceling, last-number redial, voice dialing, call reject, and the ability to transfer calls between the headset and a cell phone. The 510 has a rated battery life of six hours of talk time and promised standby time of just more than four days.