What is this?

[challenger]

Any ideas?

[DrMike]

Clothes pin, for air drying the laundry? Round part goes around the clothes line, flat part pinches the fabric. Allows the clothes to move more in winds. The clothes don't fall off the line as much as clothes pins that pinch the line.

[RB211]

Out of focus picture

[Georgineer]

It's a grostling iron

George

[reggie_obe]

For drying wet prints.

[boslab]

Vacuum connector for a Buchner funnel aka vacuum funnel, funnel sits on top of a flask with a side arm to the vacuum supply, pump or tap injector via rubber hose
Though it’s classy bronze one, the recess in the thing looks vacuum hose ( like stainless hoover pipe)
guessing btw
mark

[MrWhoopee]

I'm with boslab, the undercut circular area looks like a low pressure/vacuum flange clamp for fittings similar to tri-clover clamp.

[I make chips]

Birth control device.