Just an update to the review I posted of the Schon DSGN Stainless Pen. Shortly after my review was posted, Ian announced that he has an adapter available for his pen that will allow you to use D1 style refills instead of the Fisher Space pen refill. My preferred refill for this type of pen is the Zebra D1 and it works fine. The adapter is a plastic sleeve that accepts the D1 refill then you drop it in the pen. The only thing I noticed is that the adapter is 1 mm short compared to the Space Pen refill and the tip did not protrude from the pen fully. I just tightened the set screw a little more and it took up the slack. The price might be a little steep for what it actually is but only you can decide if $15 is worth the price to be able to use D1 refills in your Schon DSGN pen.