Pen Flushing Bulb
This 50ml bulb syringe is great for cleaning pens thoroughly. It fits over the section of your pen and can be used to suck or push pen flush, soapy water, etc through your pen to get all traces of stubborn ink out.
Unlike other cleaning bulbs, this one comes with a removable nozzle for getting into tight places and really helps with flushing some converters or filling mechanisms.
P.S. These are also great for filling sample vials of ink! It generally fits a full bottle of ink that can then be easily squirted into sample tubes.