This tool is a hemostat used in surgery and it is also used by fly fishermen when making their own flies or pulling out a hook.
It has become a second hand to me. I have a 10" and a 5 1/2" pair of hemostats and have had both of these for a very long time. They seem to always come in handy.
When making those fabric books for my DGD this were a big help. You have to sew the right sides of these panels together and leave a small opening for turning. Well, I usually leave as small an opening as possible. I only wanted a small opening for whipstitching. So, my hand wouldn't fit inside to turn the book - but - my 10" hemostat did. I guess that's why I call it an extension to my hand.
I have also used this to fill the corners of those pillows. You can put small amounts of fiberfill in the teeth, push it in the corner, hold the corner on the outside of the pillow and release the clamp. Works like a charm. P.S. I only leave a small opening in pillows also.
I also use the tips to poke out the corners of an item.
FYI - I purchased mine in store of fishing supplies. They weren't very expensive and well worth the money - IMHO