It may be a while before you need a Ballograf Ballpen refill because each writes 8000 meters before running out. Features a stainless steel tip with ball mechanism made of extremely dense tungsten carbide. Engineered to resist drying out even if the pen is left unused for a longer period of time. Blue and black medium point refills use archival ink and thus are resistant to light exposure, perfect for writing that stands the test of time. 

Single refill