AfterShokz Wireless Bone Conduction Headphones

Bone conduction headphones don't go in your ear, they lay on the side of your head on your cheekbones, vibrating sound to the inner ear.  No wires (i.e. bluetooth), so light you can wear them for hours and they include microphone pickups so you can take that phone call.  These are my answer to not being able to keep a bud in my left ear or using headphones that block out every drop of external noise.  Awesome magic!

https://www.amazon.com/gp/product/B018XNGO5A