The first retractable dry-erase marker from EXPO ?! Eliminates all the inconveniences that come with caps - ; the constant on & off, tying up both your hands. Unique Safety Seal ? valve prevents marker dry out. Bright, vivid ink is visible from a distance & specially formulated to be low odor. Quick-drying & smear proof. Use to write on whiteboards, glass & most non-porous surfaces.