For the sake of completeness, I’ll add a bit more information to zeta10's excellent description of the Gomco clamp above.
The device is used for male infant circumcision. It works by sandwiching the foreskin of the baby between 2 metal surfaces. The outer surface is tightened to crush the foreskin then the distal skin and mucousal tissue is sliced away. So far I've just rephrased zeta10.
Here is the "rest of the story".
The foreskin and the glans are fused in an infant. (This is normal, this is not phimosis and given time they would separate naturally.) So before the bell of the Gomco (the inner metal surface) can be placed over the glans a side bit of the little bit of loose foreskin at the very tip is pinched TIGHTLY with a Kelly clamp. The foreskin is pulled forward and a thin, metal, blunt tipped probe is inserted between the foreskin and the glans. All fused skin surfaces are broken using this probe to circle the glans. This causes bleeding. This in itself is a trauma. This is the reason the glans of a circumcised baby will be covered in beige/yellow granulation tissue in a few days. This is a part of healing process and should not be removed.
The bell can't be inserted with the foreskin intact so the same Kelly clamp is used to crush a line of tissue from the tip of the foreskin to the base of the glans. That tissue is then cut with a pair of scissors THEN the bell is placed over the just previously traumatized glans. The now cut open and easily manipulated foreskin is positioned using multiple little Kelly clamp pinches and then the outer metal surface (the base plate of the Gomco ) is tightened to crush the foreskin. It is left in place for the length of time the doctor feels needed to prevent bleeding and seal the 2 layers of skin together. Finally the distal foreskin is sliced off with a scalpel blade.