Quartet - QRT500113M EnduraGlide dry-erase markers offer a patented three-chamber technology that delivers bold, continuous color on dry-erase boards, ceramic, glass and other nonporous surfaces. By sending ink straight to the nib from three separate pressurized chambers, markers flow more steadily, write smoother, and erase cleanly. Convenient see-through barrel shows exactly how much ink is left. Roll-resistant cap prevents markers from drifting out of sight. Low-odor, nontoxic, quick-drying ink erases cleanly.