Powerful amplifier increases incoming sounds up to 43 dB for extra loud and clear conversations, Adjustable Tone Control lets you customize the amplifier for optimum word clarity,It makes similar sounding words crystal clear and easier to understand,Amplifier can be set to turn on automatically or manually every time you lift the handset,Audio output jack for connection to headset, neck loop or cochlear implant,Digital design minimizes background noise and enhances speech clarity,Extra bright ring flasher and super loud ringer ( 95 + dB ) with adjustable tone let you know when your phone is ringing, Bright voice mail indicator lets you know you have messages waiting for you,Missed Call Indicator lets you know that you have missed a call,"Extension in use" indicator lets you know when the extension phone is being used,Backlit, big buttons make dialing easy,Hearin! g aid T-coil compatible handset,12 memory buttons for one-touch speed dialing,Redial, Hold and Flash buttons,Desk or wall mounting,Battery back up in case of power outage (battery not included).