HA40 In-Line Amplifier by Clarity AMER-HA40

World's Loudest Telephone Amplifier
This in-line amplifier boosts incoming calls up to 100 times the normal volume (+40 dB). The portable battery-powered unit has slide controls for both volume and tone. The tone selector amplifies specific frequencies for optimum speech clarity and distinction between similar sounding words.

A special boost button maximizes amplification while blocking out feedback and background noise. Unit is compatible with most home and office telephones and is easily connected between handset and phone base. Uses 9V battery (included). A great secondary or backup amplifier at home, work or while traveling. One year warranty.