The WH220 wireless headset is compatible with the DX100, DX121, and DX210 digital wireless systems.Main Features:Single- or Two-channel operation2.4GHz frequency rangeHands-free communications5 kHz wide band audioSingle-ear, light-weight designRugged and reliableUp to 12 hours of battery lifeSpecifications:Audio:Channels: 2 audio channelsFrequency Range: 2400MHz 2483.5MHzFrequency Response: 200Hz 3.5kHzAntenna: Internal, horizontal/vertical diversityHeadset Connector: 4-pin, mini-DINMicrophone: ElectretHeadset Output: 160mW into 32 OhmsCommunication Security: 64-bit encryptionSystem Distortion: <2%Controls: Power, Volume-Up, Volume-Down, IC1, IC2, ISOIndicators: Dual-color LED (red/green)Battery Requirements: 3.6V lithium-ionBattery Life: Up to 12 hoursAntenna: InternalTransmitter:Type: Frequency Hopping, Spread Spectrum (FHSS)Transmit Power: 100mW burstModes: Momentary or LatchType: Gaussian filtered FSK, TDMAFrequency Stability: 13 ppmHarmonics/Spurious: Exceeds FCC and ETSI specificationsReceiver:Type: Frequency Hopping, Spread Spectrum (FHSS)RF Sensitivity: <-90dBm w 10-3 BERFrequency Stability: 13ppmDistortion: <2%Environmental: 32 to +122F (0 to +50C)Weight: 5.7oz (0.16kg) including battery