What is it?

My best quess would be calipers of some kind

bra fitting tool? :)

 Better stick vith double caliper.

No clue...

>bra fitting tool? :)

Where do I sign up for the how to properly use this tool class?

Looks to me as if it grabs something...Like double ice tongs.

Jim

Well it is long which tells me it was used around heat, like a forge.  It is also blacksmith made, judging by the end of the handle and the split where the inner caliper legs were formed.  I would say it was used by a smith or wheelwright for checking the size of a item while it was still hot.  My guess anyhow.  Somewhere in a book I've seen this tool. 

Calipers for carrying two dimensions at once.  Seen 'em illustrated other places.    Maybe Bealer, maybe Sloane, possibly Aldren Watson.

Double caliper for forging or blacksmith work.
Generally in some kind of "production" situation.
One side set at high limit and the other at low limit.
Like "go-nogo" gage except for hot work at a comfortable distance.

John K and leg17 nailed it on the head.  It's a IC RailRoad blacksmith calipers used in the steam locomotive shop.  I didn't show the side with the ICRR stamp.  It was shop made.  When you can make tools why buy them.  I have the pattern if anyone wants a copy send me a pm.  I was in the process of making a fancy copy when I had my operation.  Now with cold weather coming I can finally build a fire in my forge and finish them.   

It's just another version of a bull catching tool.