Fine point, nonpermanent, correctable, dry-erase marker pens write on uncoated transparencies, write-on films, laminates, sheet covers, whiteboards & overhead projection slides. Their water-soluble, color-intensive, lightfast, low-odor ink does not bleed through paper. Pens have integrated wipers on one end for minor corrections. For larger corrections, separate correctable hand wiper blades (sold separately) can be attached to the pens so they are always ready & don't get lost. No need to worry about accidental erasures, writing adheres even when film is turned over. Automatic pressure equalization prevents pens from leaking during airplane flights. Marker pens are easily refillable.