Features: 1.Easy to Use: Monaural business headset with 4 sections of single 3.5mm plug, which is in plug and play style and no driver is required. With USB sound card, it can support speaker volume adjustment, microphone mute and volume mute. 2.Noise Reduction: Our telephone headset has a built in HD microphone which can be twisted at will, giving you clear sound effect and supporting conversations even in noisy environments. 3.Durable Performance: Single sided ear headphone is made from rugged materials to ensure superb stability and durability. And the long headphone cable provides much flexibility when moving. 4.Lightweight Design: Our telephone headset offers you a pleasant wearing experience at ease. Soft ear cushions and flexible headband will not burden your ears with any uncomfort. 5.Wide Applicability: Works with devices with 3.5mm headphone jack, and with devices with USB ports when using a USB sound card. Ideal for home, offices, call centers, telemarketing, insurance, customer service, teleconferencing, etc. specification:Item Type: Telephone Headset Material: ABS Color: Black Type: Monaural Plug: 4 Single 3.5mm Plug, USB Interface (Sound Card) Function: Call, Support Speaker Volume Adjustment, Microphone Mute, Volume Mute Scope of Application: for Devices with 3.5mm Headphone Jack, Also Suitable for USB Interface Speaker s: Sensitivity: 1053dB (at 178mV 1KHz) Voice Coil Impedance: 15015 (at 1KHz) Frequency Characteristics: 100Hz-10KHz Distortion: 5% (at 178mV 1KHz) Microphone s: Directivity: Single Pointing Sensitivity: -402dB (2.0V, 2.2K, 1KHz) Distortion: 5% (at 4.5V 2.2K 1KHz) Frequency Characteristics: 200Hz-6KHz Current Consumption: 100-500A PackageList: 1 xTelephoneHeadset 1 xSoundCard 1 x Instruction Manual