The new Plantronics CS55 uses the new 1.9 GHz voice-dedicated frequency which provides users with strong sound quality for optimal voice and hearing clarity. Using the new voice-dedicated 1.9 GHz DECT standard frequency, business professionals don't have to worry about interference from nearby Wi-Fi networks, cordless telephones, and other wireless office equipment common on other frequencies. The result is a less crowded radio frequency that provides superior audio clarity with no interruptions. CS55 Key Features - Talk Time Up to 10 hours - Standby Time Up to 50 hours - Range Up to 300 ft. - Operating Frequency 1.9GHz DECT - SAR Base = 0.0055W/kg; Headset = 0.0015W/kg - Security/Privacy 64-bit digital encryption - Headset Microphone Noise-canceling - Headset Weight 26 grams - Headset Controls Volume, mute, call answer/end - Battery Type Lithium Ion Polymer - Battery Recharge Time 1.5 hours (80%) / 3 hours (100%) - Operating Temp Range +4°C (39°F) to +44°C (111°F) - Compatibility Most offi ce or PBX-based telephones - Wearing Styles Convertible: over the ear, over the head, behind the head (with accessory neckband)  It's lightweight, secure and comfortable, all day long. Click here to download Plantronics CS55 PDF brochure.