Identification of sash window mechanism

[Latlong]

Hi could anyone help me in identifying the type of this sash window mechanism?

 

[crank39]

I'm not an expert on vertical sliders but it'll probably be hung on spiral balancers but there are many strengths available for lighter/heavier sashes, then there's the removal and fitting , good luck

 

[Latlong]

Thanks, I took a few more detailed photos that might help.

 

[Latlong]

Found it, it’s a Marvin mechanism (US import)