Need help ID'ing shutter

[rorye]

Can anyone tell me what this is? Some kind of air controlled shutter? The entire piece is 6" in diameter.
TIA

 

[paul_c5x4]

It is a Luc (or similar) shutter intended to be mounted on the front of a barrel lens. Quite a useful device when shooting LF with a vintage lens and slow film - I have three or four of various sizes, some with cable release, and some with an air cylinder.

 

[rorye]

Thanks paul_c5x4