Plantronics SupraPlus HW251 Wired Mono Headset - Over-the-head - Semi-open. The Plantronics SupraPlus HW251 telephone headset has been trusted by enterprises around the world for years, designed for contact center and office professionals. SupraPlus not only meets or exceeds all specifications set by our existing world-class professional headset, but this headset is also delivers superior all-day, every-day comfort and reliability.