I put myself through college waiting tables. And every single night without fail, some guy would order decaf after dinner, then tell me a half dozen times, "You sure this is decaf? I can't drink regular, this HAS to be decaf, understand? If it's not decaf I'm calling you at 3 am and tearing you a new asshole." No need to get all excited, sir. Yes, I'm positive this is decaf. Made it myself. And, thanks, but I already have an extra asshole here at the table.
Now you don't have to worry that the lazy table jockey bringing you a cup of post-meal unleaded really poured fully loaded, and you'll be watching QVC until 4 in the morning. Just dunk a D+caf caffeine test strip into your mug and it'll tell you in about 30 seconds whether or not you're about to get buzzed.
And with their studies showing up to 30% of decafs ordered are not really decaf - or have too-high levels of caffeine - they come in handy preventing you from having a sleepless night. And ordering useless crap off late night TV.
$9.95 for a pack of 20 strips
Via 9 to Fried