.40 cal headphones
 

I'm so going to do this!!!!

That is very cool, indeed. I'm surprised someone hasn't mass produced those yet. They'd sell a lot of 'em

sweeet.

Wonder what would happen if one tried to use them in school, in an airplane, etc. Most likely you'd hear unpleasant things. But they are pretty darn cool.

That's a good point. But it's just a function of hyper sensitivity that our society seems to thrive on sadly. It reminds me of Jim Jeffries describing how different flying is in Australia vs the US.

I was at the local gun show all weekend and looked to see if anyone had caught on and sold these. But no one did. I did however almost buy a bag of .40 shells... but as I don't have a .40 cal gun, I didn't think I needed as many as they were selling (and I don't make my own ammo).

No,I never used it, i feel unsatisfactory while riding.