The Beyerdynamic Custom One Pro Headphones feature an over-the-ear design, and can be customized both sonically and physically. The four-way Custom Sound Slider adjusts the bass response by incrementally opening the flexible bass-reflex vents on the ear cups. By the time you get to the fourth and highest setting, there's so much low end that you can literally feel the air pushing out. The Custom One Pro's highly efficient 16Ω velocity drivers offer a maximum volume of 116 dB, providing you with ample headroom.
The Custom Sound Slider also changes the amount of noise isolation. On the lowest setting (the one with the least amount of bass), the Custom One Pros give you their maximum sound isolation, which is great for listening in noisy situations like planes and trains. The noise isolation process is completely passive, and doesn't fatigue your ears like electronic noise-cancelling headphones sometimes do.
The headphones can be physically changed in a couple of ways: The detachable cable is adjustable in length, going up to a maximum of 4.9' (1.5 m). The look of the headphones can be changed, as well, via the CUSTOMizer feature on the beyerdynamic website, which is scheduled to launch in September of 2012. This will allow you to purchase optional rings, covers, ear pad cushions, and headbands in a variety of colors, letting you style your Custom One Pros to your taste. The parts are all easily user-installable.