With minimlaist design inspired from the original Liliput pen, the Liliput click action ballpoint's solid aluminum or brass barrel and extraordinarily compact, pocketable size have given these pens a cult following!
Ballpoint comes outfitted with a blue 1.0mm medium point D1 type refill. Replacement Kaweco D1 refills are available in black and blue in line widths of 0.8mm (fine), 1.0mm (medium), and 1.2mm (broad). 
To refill pen, carefully unscrew push button mechanism, pull out empty refill, push in new refill, and screw assembly back on the pen barrel.