The SBD HD8-BLACK stereo headphone has 2 AAA batteries as a power supply, which has the advantage that you can simply replace the batteries. It is a reliable headphone built for ease of use, and suitable for use at events. The headphone works on 3 pre-programmed frequencies, which can be set by an easy-to-find switch. Every headphone has a power switch and a volume control. Through a hatch in one of the ear pads, you can locate and replace the batteries. The headband and ear pads are lined with skai, which ensures that they stay put. Children from 8 years and up can also use these headphones.