Poly Plantronics Spare Behind-the-head Neckband 84606-01, Spare Headband Assembly, Plantronics Headsets W440/ W440-M/ W740/ W740-M/ CS540, Durable, Comfortable. The Plantronics Savi Behind-The-Head Headband is intendedly made as a spare or replacement headband for specific Plantronics products namely the Plantronics Savi 440, 740 and WH500.