Built in the temples of the Spectacle Novax B112 is ideal for people suffering from nerve deafness. The aid has integrated circuit with push - pull output, electret mike and with continuously variable gain, tone and compression controls. It has telecoil attachment also Special Features: Continuously variable gain / tone / compression controls. Max output 132db Frequency response 350Hz - 5000 Hz Battery type - 675 Battery voltage - 104v. Battery life - 120 Hrs