Bone conduction hat means no headphones
Cynaps is a project that is currently on consorts funding site Indiegogo. The project looks like a normal baseball hat, but has technology inside that allows you to listen to music and make and receive phone calls without needing headphones or a headset of any sort. The hat has a bone conducting speaker inside transmits audio directly to your ear via vibrations.
Under the bill, the hat has a microphone that allows you to talk on your phone hands-free and a control module. The control module allows you to answer and end calls as well as control tracks in your playlist. That project is seeking $20,000 in funding and has 30 days to go. If this sounds like an interesting product to you, you should go ahead and pledge money, so far they've raised under $400.
For $50, you can get a self-install kit with all the electronics you need to fit the system into your own hat or helmet. If you don't want to install the electronics yourself, $60 will get you a hat with all the electronic components pre-installed. The battery inside the device promises between 6 and 10 hours of talking and listening to music per charge.