The SounDirector Personal Amplifier System 3 is a portable, personal amplification systems for use by individuals with mild to profound hearing disabilities designed for use in conjunction with or in place of personal hearing aids in the car, the radio or television, one on one conversations, meetings and conferences, or in other small groups. The unit combines a numbered volume control, tone control, and switchable magnetic loop pick-up coil to provide discrimination in many adverse listening environments. This system includes the SounDirector Amplifier, headphones, internal T-coil for loop reception, and instruction manual. FREQUENCY RESPONSE: 100 to 18,000 hertz with a normal transducer; 100 to 6500 with a power transducer. DISTORTION: Typically less than 3 percent. OPTIONS: A variety of transducers (headphones, stereo earbuds, etc), adapters, inductors, and neckloops are available for use with this system. Contact manufacturer for details. POWER: Uses 9-volt alkaline or NiCad rechargeable battery (not included). DIMENSIONS (HxLxW): 2 3/8 x 7/8 x 4 1/8 inches. WEIGHT: 3.2 ounces. WARRANTY: Limited 3 year warranty.