What Is It? game 299

Now it's time for our collaboration with the awesome What Is It? Blog! What is this thing? You don't have to know to win!

Place your guess in the comment section below. One guess per comment, please, though you can enter as many as you'd like. You might know the true answer, but we're going to select two winners who come up with the funniest, most outlandish guesses to win a T-shirt from the NeatoShop. However...

Please write your T-shirt selection alongside your guess. If you don't include a selection, you forfeit the prize, okay? May we suggest the Science T-Shirt, Funny T-Shirt and Artist-Designed T-Shirts?

There are more clues at the What Is It? Blog. Good luck!

Update: the pictured item is a J. M. Fox Iron Works valve grinder, used to ensure that automotive valves are properly seated. A perfectly respectable task, but we were looking for more imaginative uses for this object. Death Dodgers wins a t-shirt for his explanation:

A prototype Newton Meter - you know, the weight meters that you put an object on, and it drags it down a certain number of Newtons?
First, you take off the (removable) side sticking out, and put the thing you're measuring on a rope/string that is hooked in, replacing the part you took off to clamp it in place. Then, you drag the wheel like part to the zipper-end, and grab the zipper, and lift it up, so that gravity pulls down the wheel a certain number of grooves. That's the weight.

That's going around the world just to say it's a scale! The other winner is Zarf, who declared it to be "an 1873 Zip tie. bit of a bugger to get the end back through the eye but dammit men were men in those days." That's worth a t-shirt, too! Thanks to everyone who played this week. See the real answers to all the mystery objects at the What Is It? blog.