Have a bit of a hard time hearing occasionally, but don't want everyone to know you are wearing a hearing aid? One device you might be interested at looking at is the Stealth S.S.A Secret Sound Amplifier, a hearing amplifier designed to look like a common Bluetooth earpiece.
The amplifier can be used in either ear, and features a rechargeable lithium battery. Just remember, though – when using it, do not turn your earpiece to the speaker and say "Heh?"
$36.98