These plastic syringes are very handy for transferring ink from larger containers into empty cartridges or small containers for dipping. They can also be used to flush fountain pens. Fill the syringe with pen cleaner and push the fluid through the pen's feed and nib until it runs clear.
The blue-tipped syringe has a finer point and the clear-tipped one has a broader point. The blue-tipped syringe tip can be unscrewed, leaving a large opening for transferring thicker fluids. Both tips can be cut with scissors if you need a bigger opening.