I looked into these prior to our FOM revision requiring TSO. I was never able to find a time when they were actually in stock.

That being said, if you like the in-ear design, I went with the bose proflight recently and really like it. Of course, the price is a bit steep. Lots of the same benefits as the halo (sunglasses fit fine, able to talk to jumpseaters easily, etc...) but it's TSO'd if you're worried about it.