AfterShokz [bikeradar]

Most of us know that cycling with headphones in is a big no-no, but we might make an exception with innovation from AfterShokz
The basic idea is that, because the headphones don't sit inside your ears, you're still able to pick up the noise going on in your surroundings. 
The bud that normally goes inside your ear sits on your cheekbones and uses 'bone conduction' technology. AfterShokz say that, unlike conventional headphones that use your eardrums as transmitters, their product delivers sound through your cheekbones to your inner ears. 
The headphones were apparently developed for use by military and SWAT teams, allowing people to hear both electronic communications from members of their unit and movements by their targets at the same time.
This leaves you free to pick up sounds from your surroundings without the loss of music:
AfterShokz also claim that because the headphones don't use the eardrum to transmit sound, they reduce the risk of damage to your ears. And because the flat, rubber transmitters sit on the cheekbones, they're meant to be more comfortable and unable to fall when you're riding.