Wing Sung 618, the newest popular fountain pen in China and worldwide on August 2017, easy to separate and install, with the smooth nib and fashion design, piston fountain pen is easy to fill ink and triple ink capacity more than other fountain pen. PS. there is a lock on the turning part of the converter at the top of the barrel. You need to pull out the the turning part,then to turn it to fill ink and push it back after filling the pen(The tail of the converter at the top of the barrel has a plug, you just need to aim the plug to the socket, then press the end of the piston, the piston will be locked).If you find the nib is not align with the hood, you can unscrew the hood and rotate the nib with tongue, easy to align with the hood, then you can screw the hood tightly.You also can buy the spare nibs for this Wing Sung 618 fountain pen in my shop, ASIN is B077GB95BD, you can search it directly in.We are the professional pen store, you also can find the other great pens in my shop Imported From US