Pentel Maxiflo NLF50 fine permanent markers are a low odour marker with a unique push button system to revive the ink. The ink flows effortlessly to the last drop and to revive the color simply push the button at the top of the marker. The amount of ink remaining in the marker can be viewed to see how much is left. The Pentel NLF50 has a fine 1.0mm bullet tip with a choice of black, blue or red ink that will write on most surfaces.