Do you like Wing Sung 698's design but hate their nib? do Wing Sung 698 write a little dry for your taste? no problem.. just get yourself a Pilot Kakuno... the nib and feed fit perfectly to Wing Sung 698's section.. Just something I discover while playing with my Pilot Kakuno and Wing Sung.. yeah sure, if you brought Wing Sung 698 and Pilot Kakuno, you might as well get yourself a Twibi Eco.. but still the option is there if you wants to upgrade your Wing Sung 698.