The only markings on it are 3/16 on the front round part. The front inside part ratches back when you squeeze the handle. When you lift the side lever it is pushed forward by spring pressure. It is about 12 inches long. Any ideas on what it is used for, and who made it?

could it be tubless tire plug installer  bob w.

reminds me of a pop rivet gun.....

Thanks for the responce guys. A pop rivet tool was my first thought but I don't see how it would hold the pop rivet stem. Nothing squeezes together to hold the stem as you squeeze the handle.

Terminal crimper?

The square block that keeps the handles apart, to keep from pinching the fingers, wood or is it metal?   This is an installer of some type, it reminds me of the tool used to clip the tags on high end goods that keep them from leaving the store.   Or installing seals on packages, bags?   It has some similarity to the tool used to punch ear tags on cattle.  No name brands, says to me factory used, belongs to the corporation no need for a name.

The square block is rubber. The inside part moves back 1 cog at a time, 12 cogs total and travels about 1 1/4 inches.