The MONO twin marker writes opaquely on many materials, including glass, wood, metal, stone, and of course paper.  The ink is oil-based and waterproof, and it dries so quickly that it is virtually smudge-proof. Great news for left-handers!  It can be painted over immediately without smearing.

The Mono twin has two tips: one 0.8mm round tip and one 0.4mm fine liner tip.