日本立川鋼筆咀通用筆桿附保護蓋TACHIKAWA Universal Comic Pen Holder - comfort handle with capCG5T-40W01
This is a pen body only. A variety of nib styles are available separately. This holder is compatible with both regular and round nibs. The holder features special double rubber rings at the tip; the inner ring can take smaller round nibs and the larger ring can take regular nibs. The rubber grabs the nibs tightly, preventing shifting when drawing.