Instruction on how to fill Squeeze-Fill Fountain Pens: Press the converter bar quickly and firmly release it quickly and wait five seconds between presses so that the sac can finish expanding (and pulling ink up). Five times should be enough. Since 1931 Hero Pen factory has the reputation in China for manufacturing the best fountain pens. They are well known for the fine craftsmanship. Hero pens are very smooth and can be rated and considered as one of the best fountain pen companies of the world!