Fisher SPR1 - Blue Ink Medium Point Space Pen Pressurized Cartridge
Blue Ink Medium Point Space Pen Pressurized Cartridge. 
This is our standard 3 ½ inch Pressurized Cartridge that fits most of our pens.
The Write Out for this Cartridge is approximately 15,000 feet, depending on writing style - 3 ½ times longer than a typical ball point cartridge.
