Thread: Brno ZH101 markings

I don't know about the Brno specifically, but have you checked the flats of the barrels?

Choke markings might be in metric as it's European, eg. 17,6 or a number like that (diameter of choke in mm)

Failing that your local gunshop will have a simple choke gauge that you just pop in the muzzle. Should give you a ballpark idea.