Ideal for Lumocolor year planner 641 YP and Lumocolor memo board 641 MB. Dry and residue-free wiping of whiteboards and surfaces such as glass and porcelain. Quick drying, low odor. DRY SAFE – can be left open for days without drying up (test climate according to ISO 554). Airplane safe – automatic pressure compensation prevents the pen from leaking in the aircraft.