What is it? Game 93
It's been a while since our last What is it? game, but this one should make up for the absence: do you know what the strange tool to the left is used for?
Place your guess in the comment section - the first correct one will win a Neatorama T-shirt. If no one get it, then the funniest guess will win.
Game rules are simple: One guess per comment, please. You can enter as many guesses as you'd like. Post no URLs - let others play.
For more clues, check out the What is it? blog. Good luck!
Update 3/13/09 - The answer: A cannonball sizer, it was used as a gauge to determine if a cannonball was the correct diameter.. Congratulations to Anth who got it right!
It's Edison's first filament.