@Vladimir you asked about these two brushes a while back. I am now in a better position to comment on them . They are made just like the Olympos SP series of brushes. They incorporate nozzle caps that are Micron like - however, they are not interchangeable with either Iwata and Olympos parts. The Richpen parts are larger diameter, and different threads. Attention to detail is evident, and the finishes seem to be extremely well done.