Fanstel Amplified Speakerphone (ST45) Up To 47 Db Amplification At 115 Db Spl On Handset Frequency-Specific Amplification For Handset Auto-Selects The Best Amplification Level Up to 47 dB amplification at 115 dB SPL on handset Frequency-specific amplification for handset Auto-selects the best amplification level Business grade speakerphone up to 77 dB SPL at 20-Inch Loud ringer