Superior wideband sound thanks to optimized speaker tuning; 2 headphones for better insulation from the surrounding environment; Cable on 1 earphone only; 300deg flexible boom; Passive, noise-canceling microphone; Quick Release (QR) adapters for different connectors; Durable, lightweight, steel-reinforced headband; Leatherette ear cushions; Cable with clip; Speaker features:; Impedance: 150 ohms +/-15 ohms, ETSI wideband; Frequency range: 150 Hz to 6,800 Hz; Maximum noise level: 99 dB +/-3 dB; Microphone features:; Frequency range: 100 Hz to 10,000 Hz; Noise canceling: Passive; Sensitivity: -35 dB +/-3 dB Standard (E-STD); Boom: bendable, pivotable through 300deg ;