I have had a Wing Sung 3007 for about 2 weeks and in spite of the tiny triangular section, I like it a lot. The nib is very smooth and it had good ink flow out of the box. I do worry about what cartridge fits the 3007. The cartridge hole is way bigger than Standard International. Does anybody know definitely what ink cartridges will fit? I can refill the cartridge with a syringe, but eventually it will wear out. Thanks,