Fisher SPR1 Ballpoint Refill Medium Blue

The Space Pen pressurized refill features a tungsten carbide ball encased in a steel ball socket that prevents leaking and is designed to almost perfection. Pressurized at nearly 35 pounds per square inch so that ink is continuously fed and contains a visco-elastic, thixotropic solid-gel ink. With approximately 12000 feet of ink based on write-out machine testing, lasts 3 times longer than typical ballpoint refills.

• Comes with plastic adapter which fits any Parker style ballpoint pen
• Medium 0.7mm 
• Blue
• SPR1