The Behind the Ear (BTE) with earmold is used for more stability and power. BTE's have a hook that is attached with a tube and earmold. The earmold is a custom-made piece that is made precisely to your ear canal shape.
The tubing is able to withstand extra sound pressure without distorting the sound.
BTE with earmold are powerful; therefore, have more wider range of hearing loss that can be fitted. BTE are ideal for those who have trouble manipulating their fingers to put on hearing aid(s).