Structurally, this is a great pen. Precise machining on the threads and the barrel diamond knurling make it a pleasure to handle. Closed, its 5-5/16" long vs a Fisher space pen at 3-11/16". Without cap, its 4-13/16", long enough to write with and not feel too short in hand. The barrel dia of 1/2" also makes it esay to handle. After EDCing a Fisher for many years, it takes some getting used to not being able to fit the cap on the back end when using, but that's ok with me. Mine, in enzo red, is subtle but classic (subjective opinion). It will accept a Fisher cartridge, but if using that refill, there is a 1 mm gap between the two pen halves when fully threaded together. The cap does thread on completely with a Figher refill. Unfortunately, as another reviewer mentioned, the Schmidt refill doesn't match the quality of the pen. Every time I open the pen and start using it, a small glob of ink is on the tip, making the first written characters smudged (I'm left-handed.)