The K100 attaches easily to a car visor with the sturdy but bulky preaffixed metal clip. The unit did not budge during my jaunts in the car, and removing it from the visor required just a quick tug.
Once I got the lay of the land--the only controls you need all sit in a row--I found the K100 a cinch to use when driving. For starters, all the buttons are large. With my eyes on the road, I could easily locate the power/call button, which sits in the very middle of the row. So when I wanted to dial by voice ("Call Tim office," say), I simply held down this main button with my thumb for about 2 seconds to initiate my phone's voice-command feature. Or I could do a quick double-tap to redial the last outgoing number. The main button is surrounded by a ridged volume wheel, and the mute button and FM-transmitter control are on either side of the main button.
The buttons delivered an excellent response when I pressed them; I liked not having to press them very hard to get such well-defined tactile feedback. Even though the clickety-clack sounds are loud, it didn't bother my passengers or me.
On the volume wheel, in contrast, I needed to do quite a bit of thumbing to make the adjustments I wanted.
Voices coming through the K100 sounded clear. At the other end, according to my callers, I sounded a tad muffled overall, but folks could hear what I was talking about; generally my words did not break up, nor did listeners complain about static. Only a handful of words here and there sounded stuttered. In fact, one caller commented that--unlike other models in this particular product category--the K100 didn't sound too speakerphone-like.
The K100 did a good job of pushing traffic noise into the background, though people said that they could hear my kids' frequent squeals in those instances when I wasn't talking. (I found it very handy to have the large mute button right there within easy reach.)
The FM-transmitter button lets you hear calls and streaming audio (such as GPS directions) through the car's stereo system. You press the FM button, and an FM transmit channel is announced. Then you manually tune your car's radio to that channel, and you're ready to handle calls and tunes through the car's speakers, enhancing the listening experience. If you need to search for an available channel, no problem: The K100 lets you hold down the FM button until another channel is offered. Note: Your phone needs to support Advanced Audio Distribution Profile, or A2DP, to take advantage of the K100's streaming audio feature. For more details, check out the .
I believe that the quality of calls--especially outgoing calls--over Bluetooth in-car speakerphones must improve by leaps and bounds before anyone can describe it as superb. In the meantime, the K100's audio quality is decent, and consistently so. Considering that and its snappy design, the K100 is a solid choice as a Bluetooth companion if you need to use your phone in the car.
For more advice on selecting the right Bluetooth product for you, see "."