The Clarity Alto makes calls easier for people with hearing loss, with up to 53dB amplification. Customer support is simplified with ClarityLogic - a Clarity representative will be able to remotely evaluate your phone, and even adjust your settings for you! Features: ClarityLogic for live customer care and remote diagnostics TIA-4953 certified for mild, moderate and severe hearing loss Boost override: when on, enables amplification for all users Usable gain up to 53dB amplification Ergonomically designed tone and volume controls Loud 100dB ringer with visual indicator Speakerphone Outgoing speech amplification of 15dB 4" soft touch backlit screen with large font 10 one-touch memory buttons 2.5mm headset jack 3.5mm neckloop jack Jack for optional bed shaker (not included) 4 AA batteries for backup (not included) Dimensions: 10" x 7.67" x 4.4" Outgoing Speech Amplification (OSA) makes your voice louder for the other caller TIA-1083 compliant for hearing aid compatibility