Feature:1. [NOISE CANCELLING] Telephone headset has a built in HD microphone that can be twisted at will to make your voice large and clear. Low noise, clear conversations even in noisy environments.2. [COMFORTABLE] Ultra light telephone headset, soft ear pads and flexible headband won't put any burden on your ears. Make sure you concentrate on your conversation with long lasting comfort.3. [EASY TO USE] Cell phone headphone with RJ9 plug, plug and play, compatible with landline phones or cordless Dect mobile phones with RJ9 headphone jack, stable connection.4. [DURABLE STRUCTURE] Binaural phone headphone features a sturdy structure and materials that ensure super performance and long lasting durability. With long headphone wire for flexible movement.5. [APPLICATION SCENARIO] Multifunctional telephone earpiece, ideal for home office, call center, telemarketing, customer service, conference call, etc. Convenient and practical.How to Use:Plug and play.Specification:Item Type: Telephone HeadsetMaterial: ABSModel: H390D RJ9Color: BlackType: BinauralPlug: RJ9Function: CallScope of Application: Compatible with landline or cordless Dect phones with RJ9 headphone jackSpeaker Parameters:Sensitivity: 105±3dB (at 178mV 1kHz)Voice Coil Impedance: 150±15Ω (at 1kHz)Frequency Characteristics: 100Hz-10kHzDistortion: ≤5% (at 178mV 1kHz)Microphone Parameters:Directivity: Single PointSensitivity: -40±2dB (2.0V, 2.2KΩ, 1kHz)Distortion: ≤5% (at 4.5V 2.2KΩ 1kHz)Frequency Characteristics: 200Hz-6kHzCurrent Consumption: 100-500µAApplication: Suitable for home, office, call center, telemarketing, customer service, teleconference, etc Package List:1 x Telephone Headset