Wearing earbuds can be bad for your ears. Whenever you put them in, your ears hate it and go into defensive lockdown mode forcing you to crank up the volume. These earbuds keep that from happening while also providing better noise isolation and sound, and they do it by inflating themselves like balloons.
Your ears have a natural acoustic defense mechanism that activates whenever they encounter intense sound pressures, like those that you get when you seal off your ear canal with conventional earbuds. This defense mechanism essentially tenses up your inner ear, which has the effect of cranking down the volume of sound that you hear by up to 50 dB in an effort to protect all your delicate hearing bits. Not only does this "hearing fatigue" force most people to turn the volume of their music way up to compensate, which is bad for your ears, but it can also cause discomfort and pain.
A nifty solution to this is to use earphones with an additional membrane between the driver and your eardrum, which helps to control all that sound pressure. Instead, sound is passed directly into the walls of your ear canal where it makes it way inside your ear via bone conduction, which is essentially what happens when you listen to sounds naturally. The membrane operates like a little balloon, inflating itself using leftover air from your headphone drivers and sealing up your ear canal. This has the handy side-effects of helping to keep out external noise, and of holding your earbuds comfortably in place. Check it out:
Unofficial testing shows that the balloon earbuds sound more or less as good as conventional sets, while still doing everything extra that they promised. And since the fit is adaptive, you can open and close your mouth and even eat without changing the sound or getting all that annoying jaw noise.
The company behind this technology is currently still tweaking the design and negotiating licenses, so commercial availability is a ways off. Until then, back to your regularly scheduled ear-shattering music.