Sometimes, these devices are called receiver in the ear devices. In general, these devices tend to be resistant to feedback sound, which means that it's easier to clearly hear sounds in the environment for most users. In addition, they are relatively small and discreet, which makes them preferable for individuals who want a device that's not easily visible.
Furthermore, there are many different colors of the devices that you can choose from, which leads to a unique appearance. They also are designed to amplify high-pitched noises, which helps to ensure that you'll be able to hear everything that's going on in the environment. The cost of these products tends to be similar to the cost of other kinds of hearing aid devices, but it varies depending on the manufacturer and the type and nature of extra features that the device offers.