Darriel Caston's love of exotic materials is being showcased in our series version of his Rocket Pen. With this solid brass style, we are offering an exceptional writing tool. The relatively high specific weight of brass lends this tool a completely different feel than the usual aluminum. The patina that develops on brass with time and use gives the pen a certain vintage appeal. The easy-glide bayonet mechanism enhances the joy of writing with this pen. Diameter: 8.3/11.3 mm. Compatible to Fisher Space Pen Refill #PR4 and standard Parker-style refills. To refill, loosen the T8 Torx screw at the end of the handle.