Thread: Advice wanted: best active in-ear hearing protection

I'm looking for advice for my son. He's in the army, so he needs to listen to commands, and have hearing protection from shooting at the same time. Ear muffs are out of the question because he also wears a helmet. A recent event meant he couldn't hear instructions and took a foam plug halfway out, and had tinnitus afterwards. I have that and would like to help him avoid it if at all possible.

What in-ear protection do you use that effectively cuts loud noise (>80dB) but let's speech and ambient noise through?

Thanks.