This is a Kort nozzle for RC model boating. It is designed for a Dumas 1.5-in. propeller.
ABS filament was used.
It uses a 1/8" control rod above the nozzle and a stabilizing rod at the bottom. The top of the nozzle is marked with a small T and inside is a notch to prevent the nozzle from spinning on the control rod. I found that there was still too much play in the control rod, so I drilled a small hole through the nozzle control sleeve and the control rod then inserted a small (1/16") wire through the holes.