- Serene high definition amplified telephone - HDS (Hi-definition sound) technology for unmatched speech clarity - Amplifies your out-going voice up to 40dB - Makes the softest whisper loud, clear and easily audible - Amplifies incoming sound by 18dB - Latest DSP (digital sound processing) technology eliminates virtually all distortion, echo effects and unwanted static commonly found in other ordinary amplified phones - 9 Easy to use photo-memory buttons for one-touch dialing - 95+dB super loud ringer with adjustable ringing volume and tone controls - Two (front and side) visual ring flashers that flash when the phone rings - Battery back up for power outages (batteries not included) - Hearing aid compatible handset SIHD40S