Conference-grade speakerphone - up to 83 dB SPL at 20-Inch * Up to 52 dB amplification at 120 dB SPL * Frequency-specific amplification for both handset & headset * Auto-selects the best amplification level * RJ22 & 2.5mm headset ports * Conference-Grade Speakerphone - Up To 83 Db Spl At 20"