So I have a late model Shokz and can tell you from experience: this "technology" is just hype and bullshit. It's just a speaker placed next to your ear, that's all. At best, what's left to be conducted through your skin and bones is just residual bass, maybe less than 5%. Plugged my ears with proper earplugs and played music in the Shokz. Nearly NOTHING is left, and I assure most of it is just normal sound still leaking through the earplugs, and appropriately muffed.
I don't know how no one ever tested or debunked this thing yet. I was first made aware of this possibility when I visited a Best Buy and tried on these eyeglasses (mind me, from Bose!) with tiny speakers attached. So, they don't purport to be "bone conduction" phones. They sound pretty much the same as my Shokz, it's the same experience.
Coming to think of it, how could it possibly work in the first place? Good sound is a lot more complex than just shockwaves.
My 2 cents.
Edit: I'm not saying the end result is unsatisfactory. I'm just saying it's not conducting any significant amount of sound through the puported means (bone conduction) and that's their entire claim to fame. Bone conduction. It's the deceitful nature of the purported technology itself that bothers me. Other than that, these headphones are good for the intended result - leave your ears free to outside noise.
Edit 2. Still not convinced? I have my Shokz on me now. If I slightly remove its contact with the skin, it should go silent, right? Well, it doesn't. Now try that with the screwdriver thing and see if you can hear anything.
Edit 3. Hey, look: all these "bone conduction" headphones have clear sound openings conveniently directed to you ear canals!
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