The Hearit Perfect, model 200, is an auditory evaluation system designed for use with individuals with dyslexia, attention deficit disorder (ADD), attention deficit/hyperactivity disorder (ADHD), or hearing or auditory processing disabilities. This assessment tool offers three levels of noise reduction and can be adjusted for attenuation, auditory gain and treble range frequencies. The maximum gain at 1.6 KiloHertz is adjustable from 20 to 40 decibels (dB) and the maximum gain is adjustable from 40 to 60 dB. POWER: Uses three triple-A batteries for approximately 110 hours. DIMENSIONS: 14 x 30 x 20 millimeters. WEIGHT: 60 grams.