This is a great solution for those with condition or in need of precise sound amplification. They are unique and best. Whether you love listening or playing music, or have some issue, or just want to a new and exciting level of , our is an optimal choice for you. Features - - Material: ABS. - Size: 4.6 * 19 * 1.4cm (L * W * H). - SOUND AMPLIFIERS: precise quality Behind the Ear sound for those who require amplification. - DESIGN: The amplifiers are designed by expert audiologists. They come with digital circuitry and fully digital volume control for convenience. - EASY-TO-USE: Our amplifiers are constructed user-friendly, with easy on and off button and volume control that allows the user to make accurate adjustments in no time. - COMFORTABLE: This amplifiers perfectly fit behind the ears of both men and women. They are small in size and -light and can be comfortably worn whole day long. Specification Distortion: <=15%. Frequency: 450-5000Hz. Working Voltage: 0.2V. Working : 4mA. Weight: 4g. Package list: 1 x aid 2 x batteries 1 x manual 4 x ear