Here's a wrench I bought that I don't have a use for. I found some like it that were called "sprinkler wrenches" and Champion Brass is indeed an irrigation equipment company. Presumably made of brass but painted silver and very light weight, and a cast piece I think. I would expect brass to weigh more than a few ounces.
I don't know why you'd need a non-sparking wrench to work on sprinklers but the other pictures I saw seemed to make a point of it.  The price was right and the pictures turned out nice, so here you go!

the light weight is because it probably is aluminum in construction.

The company name is probably just "champion brass", not the tools to work on their products, which are probably brass fittings, etc. You really wouldn't want to use a steel tool on brass fittings, for fear of marring them up in short order.

It looks cast to me as well, based on the parting line seen around the spanner end.

Ditto, Alumnium is cheaper than brass, and if you can cast brass you have everything you need to cast alumnium for the most part....

Undoubtedly cast aluminum.
Al was a whole lot cheaper than brass at various times.
With the right additives it becomes very tough!

   Along about the late 50's/early 60's aluminum casting went through a wild fad. There was tons of it left over from WW11.  You can pretty much melt it on your kitchen stove in a saucepan. 
Popular Mechanics and Popular Science were full of articles.
People were casting left and right all over the nation! 

But then it was found that melting aluminum frequently, while not as bad as melting/casting quantities of lead, still, the health concerns are similar.

Occasionally, and in a small way, in hobby amounts, its fine.
  You can get away with it easy.  Cast an ashtray, etc?   No problem.

But if you start playing with a lot of it, you are playing for keeps, so watch it.
  yours Scott   

 

Here's a similar one that looks mo' brassy.

I have 3 of those. 2 aluminum and 1 brass one. I bet the the brass ones came first.

EvilDr235

i have an aluminum one. thatnks for the comments. i never knew what it was. now i can sound educated!

Found a wrench at a Tahoe estate sale yesterday.
-Don

^ That is funny, Don... I just put one of those things up on ebay... found it in a junk shop up in Sequim.

The company changed its name at some point:

Champion / Champion Brass see Champion Arrowhead /

Champion / Champion-Arrowhead, 5147 Alhambra Ave., Los Angeles, CA 90032 / sprinkler and irrigation wrenches /