EncorePro 310 Headset provides top-quality audio on both ends of your call. Voice optimization enhances conversations for optimum clarity. Headset is Quick Disconnect tested to more than 30,000 cycles for proven reliability. Wear headset all day thanks to comfortable, single-ear coverage. Adjustable band fits your head for maximum comfort. Flexible, 4mm noise-canceling microphone provides high-quality audio. Headset's frequency response ranges from 200 Hz to 6.8 kHz.