Plantronics Voyager 520/V521 Bluetooth Headset (Blue) Plantronics 520/521 Headset. Both Models are the exact same. An innovative wind screen minimizes wind noise for clear conversations A unique ear bud design focuses sound to enhance call clarity Versatile design provides a secure fit for all day wearing comfort Plantronics multipoint technology lets you conveniently switch between two Bluetooth phones with the same headset