CNET has a review of the Plantronics Discovery 665 and writes - “The Discovery 665 is slimmer and more tapered than its predecessor at 0.4×0.5×2.0 inches (the 655 measures 0.6×0.5×2.0 inches), and it weighs less than 0.3 ounce. Even though it also comes in a silver and black finish, the color scheme is reversed when compared to the Discovery 655. Everything else about the Discovery 665 headset remains the same: three different rubberized ear gel pieces for your comfort, an optional flexible ear hook for more security, a simple square multifunction button on the front, as well as two tiny rubberized buttons for the volume controls underneath. As with the 655, we weren’t too fond of the tiny buttons. Though they are raised from the surface of the headset, they still proved a bit tricky to press when the headset was worn on our ear.”

Read more about the Plantronics Discovery 665 Bluetooth headset