Need help with one

[Sertis]

This came with the group of tools/hammers/dollies/B-17 part I bought a few days ago and been wondering exactly what it is for.. I don't see any markings on it, has aluminum handles, you loosen the 3 screws to turn the center piece for adjusting the 3 slots inside. The screw on the side is marked 88/A but not sure if that was originally with it. Any ideas?

[J.A.F.E.]

It's a die holder. The shutter adjusts around the workpiece.

[Papaw]

A die holder with a thread chaser?