Forbrain headphones are one size fits all , adapting to offer an excellent fit without the need for specific adjustments. Below we provide some advice for the correct positioning and use of Forbrain : Adaptive Flexible Headband | The Forbrain headband is made of flexible materials that allow it to comfortably adapt to the shape and size of your head Bone transducers | Bone transducers (the small vibrating pads that transmit sound through the skull bones) can be positioned to ensure maximum comfort and the best sound quality. Make sure they fit snugly over your temporal bones, just in front of your ears Adjustable microphone | The microphone arm is flexible and can be adjusted to position it correctly in front of your mouth. It should be about 3-5 centimeters away from the lower lip to capture the voice optimally