Enjoy Hands-free Communication in the office VT Wireless DECT headset VT 9400 Combo was designed for Professional Business Offices. Wideband Audio for crystal-clear sound experience, advanced noise-canceling reduction to keep your focused on work with all-day comfort. Easy Call Management for operation, walk and talk at up to 350ft wireless range, up to 8 hours talk time after less than 3 hrs in full of charge. IP Phone Compatibility VT9400Dect headset in desktop phone mode and work properly with desktop phones in business office. Compatible with Electronic Hook Switch Solution. EHS Solution Available: EHS1 for Cisco7900 series Phones; EHS4 for Mitel(Aastra), Unify, Siemens Phones; EHS5 for Avaya,Shoretel and Toshiba Phones; EHS6 for Cisco Phones; EHS7 for Panasonic Phones; EHS9 for Alcatel Phones; EHS10 for Grandstream Phones; EHS13 for Polycom Phones; EHS15 for Fanvil Phones; EHS18 for Sangoma Phones; EHS21 for Digium Phones.