used taz 4, how to determine nozzle size

i got a taz 4 from a buddy with a lot of stuff(well actually 2, one is setup with dual heads)and I’m trying to figure out the nozzle size on the single head unit. I know stock is .35 but he has a few boxes with heads that are .50 (with heads in them still) is the best way to just measure the filament coming out of it there a indicator or tag somewhere?

The TAZ 4 used the Budaschnozzle hot end with the nozzle diameter engraved on the side of the hot end nozzle (just visible under the heater block):