Becky picked this little nugget up for me over here at ThinkGeek, and I must say it works well… This is not only a KeyChain, a bottle opener, and LED flashlight, but also a strobe guitar tuner!
You press the button and hold it to turn it on… It is now in Tuner Mode. You shine this at any “E” String on your Guitar or Bass, and you’ll see the string shift up and down when it is not in tune. You just adjust the tuning peg on your guitar until there is no shift or movement in the string. It rules!
You can press the button on the keychain again to move it to flashlight mode, in which the LED is a bit brighter… Press and hold the button to turn it off, and hey, open up a bottle if you got one.
One of those little things that really makes a difference.