It's sized to fit a traditional Hershey's chocolate bar. Just click on the thumbnail above to get the full-size version, print it out, trim along the edges of the graphic with scissors, fold it around a standard Hershey's Milk Chocolate bar(top flap first, then bottom flap), and give it a swipe with a glue-stick along the back to seal it up.
Update: From my traffic logs it's obvious that some folks don't realize why "Tcho" chocolate is funny to "Call of Cthulhu" fans. This might help explain it.
