A listening device is any type of technology used to capture sound. Common examples include earphones, ears, bugs, wires, stethoscopes, taps, iPods, receivers, and hearing aids. Earphones are small speakers that fit in or around the ears and are commonly used with phones, computers, and other audio devices. Ears are the organs of hearing, which allow us to detect sound waves. Bugs are small microphones that can be hidden in a room to record conversations. Wires are thin strands of metal or plastic that are used to transmit electrical signals. Stethoscopes are medical instruments used to listen to the internal sounds of the body. Taps are small devices that can be attached to a telephone line to record conversations. iPods are portable music players that can also be used to record audio. Receivers are devices that receive radio signals and convert them into sound. Hearing aids are small electronic devices worn in or around the EAR to amplify sound.