Fisher Space pen refills from the originator of the space pen. These patented, pressurised refills fit Fisher pens, the 'standard' refill is also supplied with an adaptor to allow it to be used in place of the common Parker G2 ballpoint refill, which will fit the majority of retractable ball pens. Fisher's 'Universal' refill will fit most multifunction pens as well as many mini pens that accept the standard D1 type 'mini' refill.