Tactical ears

[toreskha]

These are basically hearing aids for hunting. However, they also have obvious tactical utility. Detecting the sound of footsteps, people whispering or a careless movement may give a huge advantage.

Clearly this isn't the sort of thing that would be practical to wear on a consistent basis. It would definitely be a good SHTF item though, and training with it enough to get accustomed to having the hearing of a three-headed cat couldn't hurt.

[DarrellM5]

Those would work. I keep a Radian's electronic headset by my bed, I think they are the Hunters Ears model. They go for about $100 retail, but I picked these up on ebay for $40.