Silent Call Vibra Call Receiver
The Vibra Call is a personal alert system for people who are deaf/blind. Works like the Good Vibrations System, except it has push buttons and braille letters (no lights). When the receiver vibrates, the person wearing the unit then presses each of  four buttons to determine which signal requires atention. When the right button is pushed the receiver then vibrates again. Benefits/Features:

Easily installed, simple to operate
Range of up to 100 feet
24 hour operation (with Sleep/Alert charger)
System may be built, adding transmitters as desired
Braille instructions included

Requires battery charger.