Not a flaring tool

[HeelSpur]

Never seen one like this what is it for?

[Bill Houghton]

They're still in business, although under a new name: http://www.stridetool.com/warranty.html.  Maybe you could write them.

I know that takes a lot of the fun out of it...

[mikeswrenches]

I think the center portion was used to crimp copper tubing closed in air conditioning work.  This crimped portion was then soldered closed so the refrigerant didn't leak out.  The round portions may have been used to re-round tubing that was deformed, or to hold tubing while it was being swaged so that another piece could be inserted.

Mike

[Aunt Phil]

Pinchoff tool.

In theory it will sufficiently close a line to stop flow and allow soldering or brazing.

It is also used as a temporary emergency line shutoff, and the round holes are used to reopen the line. 
Round holes can also be used to squeeze one tube around the next smaller size if they are correctly sized as in bringing a 1/8 tube off a 1/4 tube.

[HeelSpur]

OK that makes sence to me now, an AC&Ref. tool.

I see the 1/4, 3/8, & 1/2" on top, do you know what the 5/16 measurement is for?

[Papaw]

Flip the halves to get 5/16. See the two half moons on the outside?

[HeelSpur]

Never even noticed that, thanks. :-)