The Pilot Custom 823 fountain pens are made of high-quality materials, it is available in fine finishing of transparent cap/barrel and it is a demonstrator. The material is dark enough that it blends well with the colours of the pen under most light. But holding it up against even moderate backlight shows you right away how much ink you have left. The lower portion of the cap is also translucent. The fountain pen uses plunger vacuum style filler and holds lots of ink. The filling process is relatively easy, by unscrewing the barrel end cap and pulls out the plunger and push ink to fill. This fountain pen comes with a 14K gold nib.