The Brainwavz HM9 use 40 mm drivers which have been tuned meticulously to deliver audio with accuracy, high fidelity and a deep bass extension that doesn't suffer from distortion. From the most subtle notes to deep, punchy bass, the HM9 make no compromise to deliver high-quality sound suitable for any genre of music. The large ear pads cover your ears to provide a seal that blocks out almost all outside noise, leaving your ears to hear your music only. The HM9 have been crafted from high grade, light weight aluminum, allowing for durability in any environment. Be it walking outside, relaxing at home or DJ's mixing tracks in a club, no compromise was made in style or comfort. As a plus for compact storage, the HM9 can also be folded up.