Iqua is a company based in Finland and run by a cadre of former Nokia execs. They've pooled their collective brain power into building a mobile phone accessory company. One of the company's goals is to create devices that are an "extension of your body and personality." Marketing vision aside, Iqua knows how to make a quality little headset.
The 603 Sun is about the same size as any other Bluetooth headset and comes with several different rubber ear pieces and a hook to go over your ear and hold the headset in place. About 50% of the main exterior surface is a solar cell used to collect power from any light source, be it an incandescent bulb, candle, or the sun. It also can charge with a mini-USB cable. This main surface also is the button used to turn the Sun on and off, and to connect or disconnect from calls. The ear piece is comfortable to wear, and it didn't produce any pain or soreness in my ear, even after wearing it all day long.
Pairing takes two steps. With your phone in pairing mode, simply turn on the 603 Sun by pressing where the solar panel is for about three seconds. Once it blinks a tiny little blue light, press the center of the volume toggle and hold it for about two seconds. This puts the headset in pairing mode. I was able to pair it with three different phones and a computer with no problem.
As for sound quality, it was excellent for a Bluetooth headset. It has the usual slightly muffled sound you get in Bluetooth headsets, but voices and calls were as clear as any I've ever heard via Bluetooth. I never experienced any crackling, hissing, or popping from the 603 Sun, and the volume range was wide enough to accommodate both quiet and noisy environments.
Answering and ending calls was simply a matter of pressing the side panel of the 603 Sun. I liked the fact that the entire panel served as the button. Many Bluetooth headsets have tiny little buttons on them, and they can be hard to find when you're in a hurry to answer a call. The large surface dedicated to the solar panel lets you just press the side of the 603 Sun without any fumbling around to find a button.
As for battery life, in the past 10 days, I have only charged it once. I've taken a good number of calls, and had it in stand-by mode for days on end. I've only been careful to be sure it is left in some form of light each day.
In the crowded field of Bluetooth headsets, the Iqua 603 Sun shines a little brighter than most.