Have you looked at these?
The Sordin shows a 400 hour battery life, can the battery be replaced at 401?
I picked up the DD and I use them with Samsung ear buds set to NR mode. They are great and so far are the only way I can cancel out my three bladed zero turn mower blade drone. Other headsets get a low frequency resonance rumble that is just as loud as not having them on. At the range next to a wall where incident wave compression happens all is well. With all that being said the RSO needs to be loud for people like me. My ears come first!
Before the trash gets thrown at me for blocking everything out, I have never attended a range where the lights turn Red to tell the shooters to cease fire. With RGB led lights why can’t they be placed in the shooting area where an RSO can red light one shooter or everyone? It’s a simple idea that no one is using. Green for live fire and Red for stop. Easy simple and no fancy hearing protection required.