3/16 Square DBE Wrench

[Bill vonSteuben]

I found a 3/16 Square DBE wrench marked Prestolite which I have Id'd as a tank wrench, apparently for a small acetalene tank. There are references to Indian motorcycles. Forgive my ignorance, but what is the motorcycle application for such a wrench?
Thanks for your assistance.
Bill

 

[MR.X]

I assume they're talking bout the early bikes with acetylene fueled head / tail lamps.