Got a pair of Duro(mark not legible) but design pat # 119441 is stamped on face of plier. Alloy shows similar pair with this patent and model # 2114. This pair has model # 7505 on face. Whats the difference ? Did they make these with different size box ends. This pair has 9/16 and 5/8 box ends. Alloy doesn't say what size ends on 2114 are.
These were beyond restoration when I got them,but a vinegar bath and a little buffing got them in usable if not collectible shape.

There could be different versions I suppose, the terminals on large batteries have bigger bolts in them....

Never thought about that one before....hmm...

There is a # 2115 battery plier on page 18 of the 1935 Duro catalog, but it looks nothing like yours.

Duro-Chrome 2114 Battery Pliers, Patent #D119,441

Found on this page, exact match.  http://home.comcast.net/~alloy-artifacts/duro-indestro-p2.html

Looks like the ends of the handles were box wrenches

I've seen a pair like those...  I like them...

  my question is what is difference between model 2114 and 7505 ?

Looks like none, some manufacturers change part numbers when upgrading their numbering system.

I just scored a pair marked Belden. Model 7505 with the same design patent. Now for some clean-up.

I try to use the least invasive cleaning possible, and on these pliers, I just used some SS Steel wool. Not bad results, huh?



Now, if I get out to the shop tomorrow, I might wire wheel them a bit.
By the way, the box ends are 9/16 and 5/8.

Not bad. Do you figure that's chrome plating on them, or nickel?

If plated at all, it is nickel. Pliers are made of Chrome Vanadium Steel, not to be confused with chrome plating.
The similar Duro #2115 seen in Alloy Artifacts is cadmium plated. Sure these are not.

https://home.comcast.net/~alloy-artifacts/duro-indestro-p4.html

Saw  a pair of these on the bay.  Neat tool.

Never owned or seen a pair like that.  I have 4 pair of batt. pliers, but believe those would be handy, especially working on the old stuff.

What sizes are the 12 pt box ends?

QuoteBy the way, the box ends are 9/16 and 5/8.