The Staedtler Permanent Universal Map Markers sport a universal design that can be used on nearly any surface - including overhead projectors. The ink dries in seconds, making it smudge-proof and waterproof. The ink is also permanent and low-odor despite superb color brilliance. The pen has a PP barrel and cap to keep the tip dry, but it also has a dry safe design that keeps it from drying up should it be left uncapped. With a superfine point and refillable ink, this pen is truly world class for use anywhere. Order today!