This 12-inch bronze Trippe wrench is not well documented.  The wrench head has an irregular series of stepped pins, a closed end hex wrench with a bowl-shaped socket below it. There other unusual shapes sticking out of the head of this forged wrench.

There is one non-brass colored Trippe wrench like this one on eBay right now, and the seller tentatively calls it a keg wrench.  Research I performed on the wrench some years ago, seemed to indicate this tool was used on old auto headlamps, maybe acetylene ones.

What is it?

Hmmmm! This needs some research. Very interesting wrench.

I believe that is a barrel or drum wrench. It is a multi purpose one that works on the old keg shaped barrels as well as the newer drums.

That is  brass/bronze sparkless bung wrench for steel barrels.  It would be used where a spark could be disastrous.
  Such as the paint vault I worked in at a wood toy factory.  Imagine 50 barrels of paint and a cleaning tank with over 200 gal of thinner all in one room.  The head got light working in there.

 One of these wrenchs sold in Vern Nails auction Apr of 2007. Item1927. Identified as 12 Trippe bung wrench.

There is a Trippe wrench for Trippe headlights (electric not gas) it's a small offset handled socket wrench with fine splines for the special bolts used to mount the headlights. I just found my first one a few weeks ago. Somebody is selling new ones for the antique car restorers at $35.00 each..   

I don't know if there is any connection to the headlight company and the Trippe barrel bung wrench.

http://www.29buickphotos.com/Information/Wiring-Lights/7590088_RkHJc/1/499880598_nR4fw#499880598_nR4fw-A-LB

Thanks for all the input on the odd Trippe Wrench.  Most of what I know about bung wrenches is based on the AMPCO berrylium copper alloy* wrenches I have bought (2) and sold (1).  The one I still have has 1 or 2 of the same elements that the Trippe wrench has.  The AMPCO wrench is finely finished compared to the Trippe Wrench. It will remain stained for the reasons stated below.

Berrylium Copper tools are quite common in this region, filled as it is with arsenals, explosives plants, refineries, and chemical plants (dinitrotoluene, DNT, is about as unstable and explosive as its cousin trinitrotoluene, TNT). I worked, when I was still young, in a plant which manufactured DNT, which never blew up. But OP Nitrators and gunpowder plants (700,000 lbs of smokeless powder at one time!) did blow up while I worked there.

*Berrylium copper (BeCu) is non-conductive and compares favorably to steel in material properties. That's the good news.  The bad news is that BeCu dust is carcinogenic. These tools should not be mechanically cleaned, e.g. brushed, steel wooled, sand blasted or glass beaded.